A cooking apparatus is provided. The cooking apparatus includes a main body provided with a cooking chamber, and a steam supply device generating steam to supply the steam to the cooking chamber. The steam supply device includes a water storage unit to store water, a steam generator that is supplied with water from the water storage unit to generate steam, a water supply tube to transfer water in the water storage unit to the steam generator, and a water collection tube to transfer residual water in the steam generator to the water storage unit. Accordingly, a period to put water may be increased since the residual water in the steam generator is collected.