The invention provides a mortise without load generation in bolt operation. The mortise includes a deadbolt a sub latch, a main latch, and a deadbolt operation unit to lock and unlock a door. In particular, a deadbolt operation member and a driven gear are coupled to be able to rotate by using a guide groove so that a locking protrusion and a pressing protrusion part are separated from each otheron opposite sides, and the mortise includes a control means to control a motor in order to allow the driven gear to operate the deadbolt operation member and then to be returned to an original position thereof. Accordingly, when the deadbolt is locked and unlocked manually by using a key or a handle, or through operation of the motor by an input of a password, the deadbolt operation member or thedriven gear is rotated at first in a non-load state, thereby smoothly performing locking and unlocking operations of the deadbolt.