This pharmaceutical injection device is provided with a main body case (1), a pharmaceutical syringe mounting portion (3), a piston (5), a piston feed screw (6) or the like, and a cover (25). The main body case (1) has an injection needle mounting portion (2) to which an injection needle (9) is mounted, at a first end. The pharmaceutical syringe mounting portion (3) is provided inside the main body case (1), and a pharmaceutical syringe (4) is mounted thereto. The piston (5) is provided movably with respect to the pharmaceutical syringe (4) that is mounted to the pharmaceutical syringe mounting portion (3). The piston feed screw (6) or the like drives the piston (5). The cover (25) is provided on the first end side of the main body case (1) and covers the injection needle mounting portion (2) in a state of being openable and closeable.
