A data processing apparatus that has first to fourth power modes in which power consumption becomes larger in this order, and is capable of changing into a mode selected and set by a user. A receiving unit receives the instruction for bringing the data processing apparatus into the third power mode or the fourth power mode. A first transition unit brings, when the apparatus is working in the second power mode, the apparatus into the first power mode in response to the receiving unit receiving the transition instruction. A determination unit determines which mode the apparatus is to be brought into between the third power mode and the fourth power mode in response to the first transition unit bringing the apparatus into the first power mode. A second transition unit brings the apparatus into a power mode determined by the determination unit.