A base station apparatus is disclosed that is capable of communicating with user equipment used in a mobile communication system. The base station apparatus includes a determination unit determining whether a path loss value reported from the user equipment satisfies a predetermined condition, an instruction signal generation unit, based on a result of the determination made by the determination unit, generating an instruction signal indicating whether the user equipment should reduce a transmission power value in response to a request from an other cell to reduce the transmission power value, and a transmission unit transmitting the instruction signal to the user equipment. Further, the path loss value is derived based on an average receiving quality value and a target quality value.