An improved scroll compressor having a movable scroll that orbits without being inclined. The compressor has a fixed scroll formed in the housing. The movable scroll is accommodated in the housing and mates with the fixed scroll. The movable scroll is driven by a drive shaft via a crank mechanism. A flange is formed at the periphery of the movable scroll and lies perpendicular to the drive shaft. A groove is formed in the housing. The groove is slightly wider than the thickness of the flange. The flange is slidably accommodated in the groove. Support holes extend through the flange. A pin is supported in each support hole. The ends of each pin are received in guide holes. Since engagement of the flange and the groove prevents the movable scroll from being inclined, the pin is maintained parallel to the guide holes and follows the wall of the guide holes. As a result, uneven wear of the pins and the guide holes is avoided.