diff --git a/yaml/_type/float.ts b/yaml/_type/float.ts
index b8fe8451ff2e..74f812780e72 100644
--- a/yaml/_type/float.ts
+++ b/yaml/_type/float.ts
@@ -50,8 +50,13 @@ function constructYamlFloat(data: string): number {
 
 const SCIENTIFIC_WITHOUT_DOT = /^[-+]?[0-9]+e/;
 
-function representYamlFloat(object: number, style?: StyleVariant): string {
-  if (isNaN(object)) {
+function representYamlFloat(
+  // deno-lint-ignore ban-types
+  object: number | Number,
+  style?: StyleVariant,
+): string {
+  const value = object instanceof Number ? object.valueOf() : object;
+  if (isNaN(value)) {
     switch (style) {
       case "lowercase":
         return ".nan";
@@ -60,7 +65,7 @@ function representYamlFloat(object: number, style?: StyleVariant): string {
       case "camelcase":
         return ".NaN";
     }
-  } else if (Number.POSITIVE_INFINITY === object) {
+  } else if (Number.POSITIVE_INFINITY === value) {
     switch (style) {
       case "lowercase":
         return ".inf";
@@ -69,7 +74,7 @@ function representYamlFloat(object: number, style?: StyleVariant): string {
       case "camelcase":
         return ".Inf";
     }
-  } else if (Number.NEGATIVE_INFINITY === object) {
+  } else if (Number.NEGATIVE_INFINITY === value) {
     switch (style) {
       case "lowercase":
         return "-.inf";
@@ -78,11 +83,11 @@ function representYamlFloat(object: number, style?: StyleVariant): string {
       case "camelcase":
         return "-.Inf";
     }
-  } else if (isNegativeZero(object)) {
+  } else if (isNegativeZero(value)) {
     return "-0.0";
   }
 
-  const res = object.toString(10);
+  const res = value.toString(10);
 
   // JS stringifier can build scientific format without dots: 5e-100,
   // while YAML requires dot: 5.e-100. Fix it with simple hack
@@ -91,6 +96,7 @@ function representYamlFloat(object: number, style?: StyleVariant): string {
 }
 
 function isFloat(object: unknown): object is number {
+  if (object instanceof Number) object = object.valueOf();
   return typeof object === "number" &&
     (object % 1 !== 0 || isNegativeZero(object));
 }
diff --git a/yaml/stringify_test.ts b/yaml/stringify_test.ts
index 9aa35958be61..a278b6c26724 100644
--- a/yaml/stringify_test.ts
+++ b/yaml/stringify_test.ts
@@ -226,49 +226,57 @@ Deno.test({
 });
 
 Deno.test({
-  name: "stringify() handles float types",
+  name: "stringify() handles float values",
   fn() {
-    const floats = [
-      4.1,
-      -1.473,
-      6.82e-5,
-      6.82e-12,
-      5e-12,
-      0,
-      -0,
-    ];
-    assertEquals(
-      stringify(floats),
-      `- 4.1
-- -1.473
-- 0.0000682
-- 6.82e-12
-- 5.e-12
-- 0
-- -0.0
-`,
+    assertEquals(stringify(4.1), `4.1\n`);
+    assertEquals(stringify(-1.473), `-1.473\n`);
+    assertEquals(stringify(6.82e-5), `0.0000682\n`);
+    assertEquals(stringify(6.82e-12), `6.82e-12\n`);
+    assertEquals(stringify(5e-12), `5.e-12\n`);
+    assertEquals(stringify(0.0), `0\n`);
+    assertEquals(stringify(-0), `-0.0\n`);
+    assertEquals(stringify(new Number(1.234)), `1.234\n`);
+    assertEquals(stringify(new Number(-1.234)), `-1.234\n`);
+
+    assertEquals(stringify(Infinity), `.inf\n`);
+    assertEquals(stringify(-Infinity), `-.inf\n`);
+    assertEquals(stringify(NaN), `.nan\n`);
+  },
+});
+Deno.test({
+  name: "stringify() handles float values with styles option",
+  fn() {
+    assertEquals(
+      stringify(Infinity, {
+        styles: { "tag:yaml.org,2002:float": "uppercase" },
+      }),
+      `.INF\n`,
     );
-    const infNaN = [Infinity, -Infinity, NaN];
     assertEquals(
-      stringify(infNaN),
-      `- .inf
-- -.inf
-- .nan
-`,
+      stringify(-Infinity, {
+        styles: { "tag:yaml.org,2002:float": "uppercase" },
+      }),
+      `-.INF\n`,
     );
     assertEquals(
-      stringify(infNaN, { styles: { "tag:yaml.org,2002:float": "uppercase" } }),
-      `- .INF
-- -.INF
-- .NAN
-`,
+      stringify(NaN, { styles: { "tag:yaml.org,2002:float": "uppercase" } }),
+      `.NAN\n`,
     );
     assertEquals(
-      stringify(infNaN, { styles: { "tag:yaml.org,2002:float": "camelcase" } }),
-      `- .Inf
-- -.Inf
-- .NaN
-`,
+      stringify(Infinity, {
+        styles: { "tag:yaml.org,2002:float": "camelcase" },
+      }),
+      `.Inf\n`,
+    );
+    assertEquals(
+      stringify(-Infinity, {
+        styles: { "tag:yaml.org,2002:float": "camelcase" },
+      }),
+      `-.Inf\n`,
+    );
+    assertEquals(
+      stringify(NaN, { styles: { "tag:yaml.org,2002:float": "camelcase" } }),
+      `.NaN\n`,
     );
   },
 });