To provide a lighting device capable of obtaining high luminance illumination light and downsizing the device.

A lighting device 1 includes: light source groups 10, 20, and 30 composed of a plurality of light sources that are arranged such that optical axes exist on the same plane and optical axes intersect at the same position; a light guide unit 40 that is configured by linking a plurality of prisms that guide illumination light emitted from the plurality of light sources to the direction denoted by an arrow L in the direction perpendicular to the same plane and is disposed at the same position; a movement mechanism that makes the light guide unit 40 reciprocate in the direction perpendicular to the same plane; and a controller that makes the plurality of light sources emit light intermittently by switching sequentially in synchronization with the movement of the movement mechanism. A plurality of the light source groups 10, 20, and 30 are disposed in the direction perpendicular to the same plane within the range of the reciprocating movement of the light guide unit 40.