A pharmaceutical injection device (100) comprises a main body (1), a movable member (11), a pharmaceutical holding member (10), and a first detector (28). The movable member (11) is mounted movably in the lengthwise direction of the main body (1). The pharmaceutical holding member (10) is mounted to the movable member (11), has a needle mount (17) for an injection needle (16) on one end, and houses a pharmaceutical syringe (50) containing the drug to be injected into a body. The first detector (28) is provided to the movable member (11) and detects the mounting of the needle (16) on the needle mount (17). The pharmaceutical injection device (100) improves the accuracy of detecting the mounting of a needle and/or a pharmaceutical syringe.
