An image forming apparatus includes an engine unit to execute an image forming job, a determination unit to repeatedly determine whether the image forming apparatus is in a standby state or not, based on whether the standby state to wait for execution of the image forming job is maintained for a predetermined time or not, and a controller to control the image forming apparatus to operate in a first power saving mode if it is determined that the image forming apparatus is in the standby state, wherein, in the first power saving mode, information stored in a volatile memory is copied to an internal memory and operation frequencies of a CPU, the volatile memory, and an intellectual property are lowered. Accordingly, power consumption in the standby state is reduced in a stepwise manner.