The pharmaceutical injection device of the present invention comprises an inner case (111) in which is mounted a preparation syringe (104) having an identification code (104a), a piston driving motor (115) that drives the preparation syringe (104) mounted in this inner case (111), and a code reader (112) that reads the identification code (104a) of the preparation syringe (104). A slide motor (113) is provided that drives the preparation syringe (104) mounted in the inner case (111) and/or the code reader (112), so that the identification code (104a) is read by the code reader (112).