An aspect of the present invention provides a compact light guide device and a light guide apparatus having high productivity and an even light emission property. A light guide device is made of a translucent material, and LED is disposed in a notch step portion formed by cutting at least a part of an inner peripheral surface, thereby guiding light from LED to emit the light to the outside. Particularly, in a surface and a backside of a sidewall portion of the notch step portion, the sidewall portion facing a light-emitting portion of the light-emitting element, at least an inward surface constitutes a reflecting surface diffusing the light, and a pair of facing surface adjacent to each other on both sides of the sidewall portion constitutes a light acceptance surface receiving the light reflected from the reflecting surface.