A target supply device may include: a tank including a cylindrical main body, a first end portion blocking an axial first end of the main body, and a second end portion blocking an axial second end of the main body; a nozzle provided to the first end portion of the tank and configured to output a target material contained inside the tank; and an inert gas supply unit configured to supply inert gas into the tank, in which the inert gas supply unit includes a gas flow path penetrating the second end portion of the tank and configured to guide the inert gas in a direction toward an inner wall of the main body.