A control method of a cooking apparatus. The control method of the cooking apparatus includes controlling an operation of the water supply pump to supply water to the steam generator, controlling an operation of the water supply pump for a period of time to additionally supply water to the steam generator when a level of water supplied to the steam generator reaches a position. The method includes controlling an operation of a drain pump to discharge the water from the steam generator when the period of time expires, and respectively controlling an operation of a steam heater installed in the steam generator and a bottom heater installed on a bottom surface of the cooking apparatus, when the level of the water in the steam generator reaches the position at which the water is discharged from the steam generator.