The pharmaceutical injection device of the present invention comprises a main body case (1) having a cartridge holder (7), a piston (10) that pushes out the pharmaceutical of a pharmaceutical cartridge (9) held in the cartridge holder (7), a light emitting component (34), a light receiving component (35), and a controller (25). The light emitting component (34) shines light of different colors on the pharmaceutical cartridge (9) disposed in the cartridge holder (7). The light receiving component (35) receives light that has been shined from the light emitting component (34) onto the pharmaceutical cartridge (9) and reflected by the pharmaceutical cartridge (9). The controller (25) successively shines light of different colors from the light emitting component (34) onto the pharmaceutical cartridge (9), and identifies the type of pharmaceutical cartridge (9) on the basis of the amount of light received by the light receiving component (35) for each color. The controller (25) issues a warning output if the amou
