Disclosed herein a light projection device and a head lamp for vehicle capable of highly increasing and decreasing the illuminance of a plurality of specific regions in a light distribution designed in advance with high degree of freedom. The light projection device includes: a first optical system that forms a second light radiation region; a dynamic light deflection unit configured to deflect a light beam involved in forming the second light radiation region; a second optical system configured to project the deflected light beam to form a third light radiation region; and a deflection pattern generation unit configured to deflect and output each ray of the light beam such that a direction of deflection to be imparted is dependent on a position at which each ray is incident on the light incident portion.