A drug injection device (1) comprises: a main body case (3) to which a drug syringe (4) can be attached therein; a drive means (8) which is provided inside the main body case (3) and pushes out drug inside the drug syringe (4) from a syringe needle (11); a cover (13) which opens and closes a syringe-needle-attaching-side opening (14) of the main body case (3); an outside air temperature sensor (16) which measures a first temperature which is the temperature outside the main body case (3); a display unit (20); and a control unit (21) which controls the drive means (8) and display unit (20), and obtains the first temperature at predetermined intervals. When the cover is closed, the control unit (21) causes the display unit (20) to display information on storage condition of the drug in the attached drug syringe on the basis of the first temperature.
