The present invention relates 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, the pharmaceutical injection device of the present invention comprises a main case (1), a piston (12), a drive motor (15), a buzzer (22), and a controller (18). The main case (1) has a cartridge holder (8). The piston (12) is inserted into a pharmaceutical cartridge (9) mounted to the cartridge holder (8). The drive motor (15) drives the piston (12). The buzzer (22) emits a sound that tells the user to shake the pharmaceutical cartridge (9) to mix or dissolve its contents. Before activating the drive motor (15) and injecting the pharmaceutical, the control unit (18) controls the buzzer (22) so that a sound is emitted at specific intervals to prompt shaking.