A pharmaceutical injection device includes a main body case, a cartridge holder, a latching receiver, a driver, and a manipulation component. The cartridge holder has a holding space and a holder latching component. The holding space is capable of holding a pharmaceutical cartridge. The latching receiver is configured to latch or release the holder latching component according to whether the cartridge holder is closed or open. The driver is configured to automatically release a latching of the latching receiver and the holder latching component. The manipulation component is configured to manually release the latching of the latching receiver and the holder latching component by moving the latching receiver upon being subjected to external pressure. The driver or the manipulation component is configured to release the latching between the latching receiver and the holder latching component.