Abstract: Compressor has a fixed scroll and a scroll movable in an orbit relative to the fixed scroll. The fixed and movable scrolls are equipped with a spiral wrap that engage each other and delimit variable-volume compression chambers. The spiral wrap of the movable scroll has a stepped portion extending over at least a portion of its length. At least one of the scrolls defines a passage for communication, during orbital movement of the movable scroll, between two compression chambers, with the ends of the passage terminating respectively on either side of the outer and inner walls of the spiral wrap of the scroll with the passage or inside the outer and inner walls of the spiral wrap of the scroll with the passage. The passage has a check valve for allowing fluid to flow only from the outer wall of the spiral wrap of the scroll with the passage to the inner wall.