Provided is a laser welding apparatus that performs welding by irradiating a laser beam onto a welded part, the laser welding apparatus including: a shielding gas supply unit that supplies a shielding gas to the welded part; a gas feed rate controlling unit that controls a flow rate of the shielding gas; a light intensity measurement unit that measures a light intensity of plasma light emitted from the welded part; and a rate-of-change calculation unit that calculates a rate of change of the light intensity measured by the light intensity measurement unit. The gas feed rate controlling unit controls, according to the calculated rate of change of the light intensity, the flow rate of the shielding gas supplied to the welded part.