Disclosed herein is a welding helmet in which a worker may transmit and block external light as necessary by forming a light switching window for blocking external light from a side surface of the welding helmet (helmet). The welding helmet equipped with a light switching window, which includes a helmet body portion which protects the workers face and a cartridge which blocks harmful light generated during welding to protect the workers eyes, includes a light switching window formed on a side surface of the helmet body portion such that external light is transmitted or blocked by the light switching window. The light switching window has a structure in which it may be possible to identify risk factors around a work area and a worker may block unnecessary light as necessary. Particularly, since an operating radius is enlarged, it may be possible to provide the worker with convenience.