A water pump of an electromagnetic clutch type, which feeds a coolant with pressure to a water jacket in an engine may include a belt pulley mounted at one end of a bearing shaft for being rotated on the bearing shaft by power transmitted through a belt, an impeller that is fixed to the other end of the bearing shaft, an electromagnetic actuator selectively supplying magnetic force, a clutch operating member movable along the bearing shaft to selectively engage the belt pulley with the bearing shaft by using the magnetic force of the electromagnetic actuator, and an elastic member exerting a force on the clutch operating member to support elastically the clutch operating member toward the belt pulley.