There is provided a diffractive display device having small non-uniformity of luminance within a surface, and a finder device and a camera using the diffractive display device. The diffractive display device includes a pair of substrates 24a, 24b and an optical material layer 26 arranged between the pair of substrates 24a, 24b. First illuminating means 22a for entering light through the side surface of the pair of substrates 24a, 24b and second illuminating means 22b for entering light through the side surface of the pair of substrates 24a, 24b from a direction different from the light from the first illuminating means 22a are arranged. A first portion 30a of the optical material layer 26 diffracts the light from the first illuminating means 22a and emits it from a substrate surface, and a second portion 30b diffracts the light from the second illuminating means 22b and emits it from the substrate surface.