A noise control device for a steel door includes a buffer, a shock-absorbing member, a stopping member, or only includes a colliding member. The noise control device is installed at any location of a steel door and a casting where noise may be generated when the steel door is closed or opened. The buffer consists of a cylinder, a lower sponge, a coil spring, a rod, and an upper sponge and possibly a colliding member. The buffer can be mainly installed on a deadbolt groove of the casing. The shock-absorbing member may be fixed on the steel door or the casing for reducing sound. The stopping member is fixed on the steel door to face the outer end of the buffer. The noise control device can reduce noise generated in opening and closing as much as possible and preventing the both from disfiguring or denting.