A variable capacity rotary compressor having a slot defined between eccentric bushes, a latch pin fitted to a rotary shaft so as to be latched to the slot, and a restraint unit for restraining the eccentric bushes upon rotation of the rotary shaft. The restraint unit includes a restraint member mounted in the rotary shaft, a supporting shaft extending from the latch pin to be inserted into the hollow portion of the restraint member, and a return spring interposed between an outer circumference of the supporting shaft and the restraint member to move the restraint member inward toward the center of the rotary shaft when the rotary shaft is not rotated. The restraint unit is easy to manufacture and install and to ensure smooth operation thereof.