PURPOSE: To obtain uniform lighting for an endoscope with a simple structure by arranging a liquid-crystal element or electrochromic element capable of varying in transmissivity partially according to an image plane illuminance distribution between the incidence terminal of a light guide and a light source.

CONSTITUTION: The liquid-crystal element 22 is arranged between a condenser lens 7 and the incidence terminal of a light guide 21 constituted so that individual fibers almost correspond to each other at the incidence terminal and projection terminal. This liquid-crystal element 22 has liquid-crystal 22b between two electrodes 22a and is divided into plural parts, which are operated independently of one another. Respective parts of the liquid-crystal element 22 are made opaque selectively through a liquid-crystal driving circuit 23 on the basis of a control signal from a detecting circuit 12 and the flux distribution characteristics on an observation body S by this lighting system are varied properly; to correct the illuminance distribution of an observation visual field uniformly.