A radio base station used in a mobile communication system is disclosed. The radio base station includes a scheduler configured to allocate one or more resource blocks, which are defined by a predetermined bandwidth and a predetermined transmission time interval, to a user device; and a reporting unit configured to report scheduling information indicating radio resource allocation to the user device. The scheduler is configured to generate the scheduling information such that downlink data channels and downlink control channels are transmitted using the transmission time interval as a transmission unit and uplink control channels are transmitted using an integral multiple of the transmission time interval as a transmission unit.