An irradiation system (10) includes: a light position detection unit (4) that detects a light position (A) of an oncoming vehicle from a captured image captured by an imaging device (2) that captures an image ahead of a host vehicle; a driver position calculation unit (8b) that calculates as a driver position (C) : a position shifted upward by a difference in height (D height ) between the light position (A) and a driver's face position (C) in a predetermined vehicle and shifted in a first horizontal direction by a first distance (d light -d driver ) from the light position (A) detected by the light position detection unit (4) ; a shaded area generation unit (8c, 80c) that generates as a shaded area : a first area (AB'C) having vertices respectively set at the light position (A), the driver position (C) and a position (B') shifted in a second horizontal direction, opposite to the first horizontal direction, by a distance (2*d light ) between a pair of lights (A, B) in the predetermined vehicle from the driver position (C); and an irradiation unit (9a, 3) that irradiates an area ahead of the host vehicle while shading at least the shaded area generated by the shaded area generation unit (8c, 80c).