A device and method controlling working state change of a small cell and a base station including the device. The device includes: an information acquiring unit that acquires interference between a small cell to be controlled and an adjacent small cell and/or load of the small cell to be controlled or load distributed by other small cells and to be borne by the small cell to be controlled; and a state change determination unit that determines working state change to be performed by the small cell to be controlled according to the acquired interference and/or load. The working state includes multiple sleep levels from low to high. A sleep degree of the small cell to be controlled in a low sleep level is less than a sleep degree of the small cell to be controlled in a high sleep level, the working state change being performed among multiple sleep levels.