The disclosed is a light guide unit and a surface illuminator illuminating a liquid crystal display (LCD). The light guide unit (100) is composed of a surface lighting light guide (30) having a light emitting major surface (30a) and a light receiving side surface (30c); a channel light guide (20) having optical cores (21) to form a fiber optic channel array having light entrance core surfaces (21a) and light exit core surfaces (21b); and a distribution light guide (10) having a light distribution guide surface (10d) and a light receiving portion (10b) receiving light from the LED (200). The light guides (10, 20 and 30) are positioned respectively in that order to form a light guide unit (100). Each width (w1) and/or a pitch (p) of the optical cores (21) may change in accordance with a distance from the light receiving portion (10b). The channel light guide (20)/the distribution light guide (10) may have a linear shape or a nonlinear shape with "L", "U" or "O" shape. The distribution light guide (10) may have a "V" shaped or rectangular reflector (40) with opposed surfaces (40a, 40b) to reflect light (L) from the LED (200) to face the reflector (40).