diff --git a/src/index.ts b/src/index.ts
index 000765f..e9cb538 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -176,6 +176,7 @@ function makeMainHeader(output: string) {
     result += '#include <string>\n';
     result += '#include <vector>\n';
     result += '#include <cstddef>\n';
+    result += '#include <map>\n';
     result += 'extern "C" {\n\n';
     result += makeHeaderPart(true);
     result += '\n// End C++ Mode\n';