The invention provides a shell punching device. The shell punching device comprises a support, an upper pressing plate, a lower pressing plate, a female die, an outer male die and an inner male die. The upper pressing plate is arranged on the support, the lower pressing plate is arranged on the support and located below the upper pressing plate, and the lower pressing plate and the upper pressingplate can move oppositely to clamp a base material with a shell to be punched in a matched mode. The lower pressing plate is provided with a lower through hole with the shape matched with the to-be-punched shell of the base material in shape, the female die is vertically slidably arranged on the support, located below the lower pressing plate, and provided with a lower punching head vertically slidably matched with the lower through hole. A cavity is formed in the top of the lower punching head, and circular corners are arranged at the tops of the outer walls of the cavity. The outer male dieis vertically slidably arranged on the support, located above the upper pressing plate and provided with an outer punching head capable of being matched with the lower through hole, and the outer punching head is internally provided with a through passage corresponding to the bottom wall of the cavity. The inner male die is provided with an inner punching head vertically slidably matched with thepassage. The circular corners can relieve stress concentration of the stretching part of the base material, breakage of the base material is prevented, meanwhile the outer punching head can further stretch the base material, and space waste is avoided.