PURPOSE: To constitute a neuro chip without adding a sigmoid function computing element by setting the light-emitting characteristic of light emission elements to be a threshold functional one and feeding back the output of light-receiving elements corresponding to the light emission elements to the light emission elements.

CONSTITUTION: A light emission element part 3 containing plural stripe-formed light emission elements 2, the optical shutter array 4 of a matrix array-form and a light-receiving element part 6 containing stripe-formed light receiving elements 5 extending in a direction perpendicular to the extending direction of the light emission elements 2 are sequentially laminated. Respective stripe- formed light-receiving elements 5 consist of photodiodes and they are connected to power sources E1-E4 through resistances R1-R4, whereby an inverse bias is impressed. Since the band gap of the semiconductor of a collector layer 23 is made larger than the band gap of a base layer 22 in the light emission elements 2, emitted light is coupled again in the base area 22.