diff --git a/vllm/engine/arg_utils.py b/vllm/engine/arg_utils.py
index c058001ceb97..dd1072da0844 100644
--- a/vllm/engine/arg_utils.py
+++ b/vllm/engine/arg_utils.py
@@ -711,7 +711,7 @@ class EngineArgs:
             "--mm-processor-cache-gb",
             **multimodal_kwargs["mm_processor_cache_gb"])
         multimodal_group.add_argument("--disable-mm-preprocessor-cache",
-                                      type=bool,
+                                      action="store_true",
                                       deprecated=True)
         multimodal_group.add_argument(
             "--interleave-mm-strings",