The invention discloses an automatic door closer. The automatic door closer comprises a frame fixedly arranged on a ceiling, and the frame is internally and fixedly provided with an inner cavity and aleft-right symmetrical sliding cavity penetrating through front and back. The frame is internally provided with a fixed block, and the fixed block is internally and fixedly provided with an identifier. A rotating motor is fixedly arranged in the upper end wall of the inner cavity, and an output shaft of the rotating motor extends into the inner cavity. A driving gear is fixedly arranged on the lower end surface of the output shaft of the rotating motor, a driven gear is arranged on the left end surface of the driving gear in a meshing mode, and the driven gear is internally and fixedly provided with an extension output shaft. The automatic door closer is simple in structure and convenient to use, the simple door opening and closing process through simultaneous working of a variety of transmission mechanisms can be realized, doors in multiple directions can be opened at the same time so that personnel can pass through safely, and the passage speed in the process of a large number of people is speeded up.