In a scroll compressor provided with a fixed scroll member (4) and a movable scroll member (3) which define a plurality of compression spaces (6) therebetween in cooperation with each other, a hole (32) is formed to the fixed scroll member to be communicable with adjacent ones of the compression spaces. The adjacent compression spaces are different from each other in pressure when the scroll compressor is driven. A piston valve (33) is disposed in the hole and controls communication between the adjacent compression space through the hole. The compression spaces are movable with volumes reduced by movement of the movable scroll member.