image forming apparatus including : external cover covering outer side of side wall of housing storing image forming portion , and having exhaust outlet ; equipment storage space formed between side wall of housing and external cover ; opening formed in side wall and allowing inside of housing to communicate with equipment storage space ; exhaust fan disposed in equipment storage space and taking in air from housing via opening and exhausting air from exhaust outlet ; heat generating equipment disposed in equipment storage space ; and duct connecting air outlet of exhaust fan and exhaust outlet . communicating portion , which allows inside and outside of duct to communicate with each other , is formed in wall of duct located on heat generating equipment side .