PURPOSE: A closer for a door is provided to fix a door to a random position while being opened and to close the door by restoring a hydraulic line in the event of fire. CONSTITUTION: A closer for a door comprises a closer(10), a unidirectional ball valve(30), a locking lever(40), and an actuating unit. The closer is equipped with a hydraulic line(11) for sending oil by a piston(20). The unidirectional ball valve is elastically supported by a spring(31) on the hydraulic line. The locking lever is installed to support the ball valve. The actuating unit moves back and forth the locking lever.
