The invention provides a bi-directional light control thyratron transistor chip, an optical triggering coupler and a solid-state relay. A first light control thyratron transistor section and a second light control thyratron transistor section are arranged on a surface of a semiconductor chip. Each light control thyratron transistor section has a PNPN section. The PNPN section comprises a positive electrode diffusion region in a conductive type, a substrate in another conductive type, a control electrode diffusion region in a conductive type and a negative electrode diffusion region formed in the control electrode diffusion region in another conductive type. The distance of the cut surface to the control electrode diffusion region is below 400 micrometers. Thus, a few of minority carriers generated at the first light control thyratron transistor section side during connection are collected to the cut surface at the first light control thyratron transistor section side before migration. Schottky barrier or a channel separation region cannot be formed, rectification characteristics are raised greatly, increase of the chip area can be inhibited and load is controlled through light triggering by one chip.