PURPOSE: To provide an optical axis adjusting device which efficiently makes light generated by a light emitting means incident on the light guide of a light transmission apparatus by converging by a light converging means and easily performs optical axis adjustment.

CONSTITUTION: This device is provided with a lamp 2, a lens 3 which converges the light generated by the lamp 2 and makes it incident on the incident terminal of the light transmission apparatus held at a prescribed position, a light receiving element 9 which captures the position state of an incident terminal, and a converged light position adjustment control means which performs adjustment to align a converged position by the lens 3 with the position of incident terminal of the light transmission apparatus, and the light generated by the lamp 2 is converged by the lens 3, and an optical axis can be adjusted at a position where the light can be efficiently made incident on the light guide of the light transmission apparatus.