PURPOSE: To smoothly, securely, and automatically close a door by fitting a coupling that a door opening action acts on a closing spring structure and a buffer structure to a device operating the door closure structure attached to a door sill.

CONSTITUTION: This door closure device 10 is provided with a case 11, in which a spring closure structure 12 and a buffer structure 13 are inserted, and the buffer structure 13 is disposed in an operating slider 14 containing a cylinder 15 and a movable piston 16. A restricting opening 37 in the piston 16 compresses a turning-back spring 36 of a buffer to actuate a thlottle 35 extruding oil from the cylinder 15. When a closing shaft 24 rotates on opening the door, a closure cam disc 22 acts on a tie bar 32 of the slider 14 through a closure trunk 17 or the like. Furthermore, a tie bar 32 acts on the piston 16 of the buffer structure 13, so that the slider 14 compresses the closure spring 39 and the hydraulic pressure is attenuated, while the door is kept open. In this way, the opening force of the door can be not only mechanically restrained but also restrained hydraulically.