A vane compressor has at least one of a front-side member and a rear-side member thereof formed with a suction chamber opening toward a cam ring, which has a substantially arcuate or annular shape and extends around a drive shaft. The cam ring has one end face formed with a refrigerant inlet port for supplying a low-pressure refrigerant into compression chambers formed between vanes. Alternatively, a front head is arranged on one end face of the cam ring. A shell encloses another end and an outer peripheral surface of the cam ring and holds a movable plate in a state opposed to the other end face of the cam ring such that the movable plate can be moved along a central axis of the drive shaft. An inside of the shell and the movable plate defines a high-pressure chamber therein. Each adjacent pair of the vanes, the front head, and the movable plate defines a compression chamber therein. The shell has a front-side end extending to an outer peripheral surface of the front head and fixed to the outer peripheral surface of the front head. The outer peripheral surface of the cam ring and an inner peripheral surface of the front-side end of the shell defines a low-pressure space therebetween. The cam ring is formed with an inlet port opening through an outer peripheral wall thereof for supplying a low-pressure refrigerant into the compression chambers during a suction stroke.