A middle illuminated button switch including a printed circuit board (PCB), a base and a cover. A guide core is arranged between the base and the cover, a through hole is arranged at the bottom of the base and under the guide core. A light guide groove is provided at the lower end surface of the guide core. A light-emitting element is arranged on the upper end of the PCB, and the light-emitting element is inserted into the base from the through hole and embedded in the light guide groove. Since the light-emitting element is embedded in the base from the bottom to the top, and the light is emitted to the outside from the middle through the guide core, so as to realize the light-emitting effect in the middle of the button.