diff --git a/ext/json/generator/depend b/ext/json/generator/depend
index a69d0f89b7..d9160673a2 100644
--- a/ext/json/generator/depend
+++ b/ext/json/generator/depend
@@ -178,5 +178,6 @@ generator.o: $(hdrdir)/ruby/st.h
 generator.o: $(hdrdir)/ruby/subst.h
 generator.o: $(srcdir)/../fbuffer/fbuffer.h
 generator.o: $(srcdir)/../vendor/fpconv.c
+generator.o: $(srcdir)/../vendor/jeaiii-ltoa.h
 generator.o: generator.c
 # AUTOGENERATED DEPENDENCIES END