This invention discloses a door opener, comprising a shell consisting of an upper cover plate (1) and a lower cover plate (2). The key is that a pushing device for pushing the door to rotate is provided in the shell. An end of a driving device, which has one or more springs, can drive, via a rotating member (3), the pushing device to rotate. A locking/releasing device, which cooperates with the driving device, is provided at the other end of the driving device. The structure of this invention is unique. It allows the door to be conveniently opened and will not cause any possible harm to the users.