diff --git a/src/objects/bigint.cc b/src/objects/bigint.cc
index 23511d9977..70d0d831fc 100644
--- a/src/objects/bigint.cc
+++ b/src/objects/bigint.cc
@@ -530,14 +530,16 @@ MaybeHandle<BigInt> BigInt::FromObject(Isolate* isolate, Handle<Object> obj) {
   }
   if (obj->IsString()) {
     Handle<BigInt> n;
-    if (StringToBigInt(isolate, Handle<String>::cast(obj)).ToHandle(&n)) {
-      return n;
+    if (!StringToBigInt(isolate, Handle<String>::cast(obj)).ToHandle(&n)) {
+      THROW_NEW_ERROR(isolate,
+                      NewSyntaxError(MessageTemplate::kBigIntFromObject, obj),
+                      BigInt);
     }
-    // ... else fall through.
+    return n;
   }
 
   THROW_NEW_ERROR(
-      isolate, NewSyntaxError(MessageTemplate::kBigIntFromObject, obj), BigInt);
+      isolate, NewTypeError(MessageTemplate::kBigIntFromObject, obj), BigInt);
 }
 
 Handle<Object> BigInt::ToNumber(Handle<BigInt> x) {
diff --git a/test/mjsunit/harmony/bigint/basics.js b/test/mjsunit/harmony/bigint/basics.js
index 86d585e422..7ae51a04a0 100644
--- a/test/mjsunit/harmony/bigint/basics.js
+++ b/test/mjsunit/harmony/bigint/basics.js
@@ -22,8 +22,8 @@ const six = BigInt(6);
 
 // ToBigInt, NumberToBigInt, BigInt
 {
-  assertThrows(() => BigInt(undefined), SyntaxError);
-  assertThrows(() => BigInt(null), SyntaxError);
+  assertThrows(() => BigInt(undefined), TypeError);
+  assertThrows(() => BigInt(null), TypeError);
   assertThrows(() => BigInt({}), SyntaxError);
   assertThrows(() => BigInt("foo"), SyntaxError);
 }{