IMAGE DISPLAY DEVICE

Provided is an image display device that attains see-through characteristics and visual perceptibility with a simple structure. An image display device includes a frame, a signal generation unit (light source unit) that generates signal light L1 that is a TE wave, a scan light emission unit that is provided with a light scan unit 42 (light scanner) that scans the signal light L1, a reflection unit 6 (reflecting optical unit) that reflects the signal light L1 scanned by the light scan unit 42; a diffracting optical unit 9 that includes a pair of diffraction gratings whose grating patterns are equivalent to each other and diffracts the signal light L1 reflected at the reflection unit 6; and a polarizing plate 8 (polarization selection unit) that is located at an opposite side in relation to the diffracting optical unit 9 with respect to the reflection unit 6 and allows outside-world light L2 that is a TM wave to pass toward the reflection unit 6, wherein the diffracting optical unit 9 diffracts the signal light L1 and does not diffract the outside-world light L2. The signal light L1 is split into plural beams at the diffracting optical unit 9 to enter the eye EY of a user.