A detent escapement 100 includes an escape wheel 110, a balance 120 which has an impulse pallet 122 and an unlocking stone 124, and a blade 130 which has a locking stone 132. A one side actuating spring 140 which can contact the unlocking stone 124 is provided in the blade 130. When a working reference line 129, which is a line connecting the rotation center of the balance 120 and the rotation center of the blade 130, is set to a reference, the one side actuating spring 140 is disposed at an angle so that a distance of the tip of the one side actuating spring from the working reference line is increased as the tip is separated from the rotation center of the balance 120 in a side opposite to the side at which the escape wheel 110 is present. The one side actuating spring 140 is disposed between the locking stone support arm 131 and the one side actuating spring support arm 133.