To provide a light projection device capable of suppressing local variance in light intensity at scanning with a mirror part, and to provide a light projection device for vehicle.SOLUTION: A light projection device 100 comprises: a light source 1 which has a plurality of light emission parts 10 arranged side by side in a predetermined direction; a plurality of convex lenses 2 which are irradiated with light from the plurality of light emission parts 10 and converge the light, and are provided as many as the plurality of light emission parts; an optical scanner 4 which has a mirror part 4a scanning light passed through the plurality of convex lenses 2 in the arrangement direction of the plurality of light emission parts 10 and a driving source 4b swinging the mirror part 4a; and a projection lens 3 which is arranged between the plurality of convex lenses 2 and the mirror part 4a, or at a position where the scanned light is projected from the mirror part 4a. The plurality of convex lenses 2 are arranged side by side in a predetermined direction at intervals so that light transmitted through the plurality of convex lenses 2 to be converged is close in a stationary state.SELECTED DRAWING: Figure 2