A network cooperation-based low power type charged broadcasting set-top box and a controlling method therefor, the set-top box sub-dividing a standby mode of the set-top box into an active standby mode, in which only background functions are processed without processing a main function, and a passive standby mode, in which no functions are processed; extending the passive standby mode occupation time to more than that of the active standby mode; and including a way of transitioning between operating modes by exchanging information regarding the set-top box through an inter-cooperation between a charged broadcasting network and the set-top box, thereby reducing the power consumption of a processor (SoC) which processes multimedia contents and minimizing the power consumption while the set-top box is in standby mode.