An image projection device includes: a first mirror oscillating to scan an image light beam forming an image projected onto a retina of a user; a light source emitting the image light beam and a detection light beam to the first mirror at different timings; a second mirror having a first region reflecting the image light beam reflected by the first mirror to the retina and a second region reflecting the detection light beam reflected by the first mirror in a direction different from a direction in which the image light beam is reflected, and scanning neither the image light beam nor the detection light beam reflected by the first mirror; a detector detecting the detection light beam reflected by the second region; and a controller adjusting oscillation of the first mirror and an emission timing of the image light beam based on a detection result by the detector.