A portable engine generator has a box-shaped case defining an internal space for holding an engine and an electric generator to be driven by the engine. The case is provided with carrying handles. The portable engine generator is provided with a cooling air passage through which fresh air as cooling air flows into the internal space while the engine is in operation. An inward depressed part is formed in a front cover of the case on the side of the internal space with respect to the carrying handles. The carrying handles and the inward depressed part define the cooling air passage. The cooling air passage serves as a hand space into which human hand is inserted to grip the carrying handles.