The invention discloses an automatic folding machine. The automatic folding machine comprises a device main body, a folding device arranged in the device main body, a mark pressing device arranged inthe device main body, a paper feeding device arranged in the device main body, and an illumination device arranged on the device main body, wherein the folding device comprises a first cavity formed in the device main body; communicated second cavities are symmetrically formed in the inner walls of the left side and the right side of the first cavity; a third cavity is formed in the inner wall ofthe lower side of the first cavity in a communication manner; a fourth cavity is formed in the inner wall of the rear side of the first cavity; a first slide block is slidably arranged in the first cavity; and a first spring is fixedly connected between the upper end of the first slide block and the inner wall of the upper side of the first cavity. The device is simple in structure, convenient touse, and capable of automatically completing many folding working for paper, thereby saving the labor; and moreover, the device is capable of working for a long time, high in efficiency, and worthy ofrecommending.