To display a high-quality picture by restraining the distortion of the locus of a light beam with respect to linearity within a fixed amount.

In this picture display device displaying a picture whose aspect ratio is 4:3 or 16:9 by deflecting a light beam from a light source 1 in horizontal and vertical directions by a light deflecting mirror 2; the light source 1 and the mirror 2 are arranged in such positional relation that the light beam is made incident on the mirror 2 so that a deviation angle α from a surface orthogonal to a mirror rotary shaft for deflection in the horizontal direction may be within 13° and a deviation angle α from a surface orthogonal to the mirror rotary shaft for deflection in the vertical direction be within 28° when the picture aspect ratio is 4:3, or the light beam is made incident on the mirror 2 so that the deviation angle α from the surface orthogonal to the mirror rotary shaft for deflection in the horizontal direction may be within 10° and the deviation angle α from the surface orthogonal to the mirror rotary shaft for deflection in the vertical direction may be within 44° when the picture aspect ratio is 16:9.