The present invention discloses a toy gun, and relates to the technical field of toys. In the present invention, a driving mechanism drives a gear set to rotate, and the gear set drives a piston to move reciprocally in a cylinder body, so that the piston compresses air in the cylinder body, and high-pressure air is ejected from an air nozzle. After a gel ball is loaded into a gun barrel, since the air nozzle is inserted at one end of the gun barrel, the compressed air ejected from the air nozzle pushes the gel ball out of the gun barrel, thereby realizing the firing of the gel ball. Compared with the toy gun that cannot fire bullets in the traditional art, the present invention improves the playability.