diff --git a/src/main.lua b/src/main.lua
index a433404..4e68732 100644
--- a/src/main.lua
+++ b/src/main.lua
@@ -33,6 +33,7 @@ local function load_map(map_file_name)
     file:open("r")
     text = file:read("string")
   end
+  file:close()
 
   local map = json.decode(text)
   nodes = map.nodes or {}