Provided is a dog clutch actuator comprising a sleeve (10) having dog teeth made engageable with the dog teeth formed in a power transmission shaft (30) and made movable in the axial direction, and a plunger (14) for moving together with the sleeve (10). The plunger (14) is axially moved through a yoke (16) by electric currents to flow through coils (18 and 20). The dog clutch actuator is so characterized by the shapes of the plunger (14) and the yoke (16) that a sucking force increases in the engaging direction, when the dog clutch is engaged, and decreases in the disengaging direction, whenthe dog clutch is disengaged.