A conventional optical illumination device has a problem in which uneven brightness appears in an inclining direction when an illuminated region inclined with respect to an optical axis is illuminated. An optical illumination device is formed by using a front optical illumination system 7, an eccentric lens 9, and a relay lens 11. The front optical illumination system 7 is composed of a lamp 1, an elliptical-surface mirror 2, a UV-IR cut filter 3, a condenser 4, a first lens 5, and a second lens 6. The relay lens 11 conjugates a second light-emitting surface 10 and a third light-emitting surface 12 that are inclined with respect to an optical axis 15. The eccentric lens 9 is made eccentric with respect to an optical axis 14, effectively emits light, which is emitted from the second lens 6, to the relay lens 11, and inclines the second light-emitting surface 10 in a direction in which brightness gradient appearing on the relay lens 11 is canceled. |