To provide a thin compressor or vacuum device having a motor that is prevented from becoming hot and ensures torque.

A compressor or vacuum device includes: cylinders and a crankcase; a piston that is arranged in the cylinders and the crankcase; and an outer rotor motor that allows reciprocating motion of the piston. The outer rotor motor includes: a stator; coils that are wound around the stator; a rotating shaft; a yoke that is coupled to the rotating shaft; and permanent magnets that are fixed to the yoke. The yoke has vents formed therein.