Certain embodiments of the present invention relate to a pharmaceutical injection device, and it is an object thereof to optimize the mixing of pharmaceutical in a pharmaceutical cartridge. To achieve this object, a pharmaceutical injection device may comprise a main case, a piston, a drive motor, a buzzer, and a controller. The main case has a cartridge holder. The piston is inserted into a pharmaceutical cartridge mounted to the cartridge holder. The drive motor drives the piston. The buzzer emits a sound that tells the user to shake the pharmaceutical cartridge to mix or dissolve its contents. Before activating the drive motor and injecting the pharmaceutical, the control unit controls the buzzer so that a sound is emitted at specific intervals to prompt shaking.