Lubricant oil, separated from compressed fluid and stored in an oil storage chamber formed beneath a motor, is introduced via an internal oil supply passage to an attachment groove formed for installing a main bearing. The lubricant oil passes through the main bearing, and flows toward a compressor. The lubricant oil is also supplied to an oil supply hole formed inside a rotation shaft of the motor via lubricant oil grooves, and lubricates and cools a needle bearing. Accordingly, axial length of housing protruding portion is reduced, and thereby reducing an entire axial length of the electrically-driven compressor apparatus.