To provide a door closer which can be opened by light force, can automatically close by letting go the door at a low speed and can be built in the door.

In a door closer wherein a body case 1 is fixed to a position on top of the upper box or the door frame of a door, and the drive rope 5 led out in the orthogonal direction from the body case 1 is fixed to the other position, and which opens the door resisting the spring force of the spring 6 built in the winding drum 3 of the drive rope 5 and winds the door in the closing direction by the energizing force of a spring by canceling external force, the door is closed by at a low speed by a one way clutch 7 operating through a plurality of gear devices, speed increasing gears 8 and 9 and the centrifugal brake mounted on a brake drum 10. The one way clutch is operated only when the drive rope is wound.