Provided is a light guide, in which: at least one of a reflecting part or a light exit part has a light condensing action in a direction intersecting a predetermined direction; the at least one of the reflecting part or the light exit part includes diffusing parts arranged in the predetermined direction; the diffusing parts include: a first curved surface having a first degree of diffusion in the predetermined direction for a sparse region of light sources; and a second curved surface having a second degree of diffusion, which is lower than the first degree of diffusion, in the predetermined direction for a dense region of the light sources; and each of the first curved surface and the second curved surface has a shape corresponding to a part of a cylinder extending in a direction orthogonal to the predetermined direction in which the light sources are arrayed.