A washing machine (1) in which the laundry of poor heat-resistance is sufficiently wet so that a water curtain layers are formed at the laundry, thereby aiming to prevent the laundry from being stained and damaged when the laundry contacts the steam. Cold water is supplied simultaneously with injection of the steam so that the real temperature of the steam contacting the surfaces of the laundry is lowered, thereby aiming to prevent the laundry from being stained and damaged when the laundry contacts the steam.