A disclosed radio base station is used in a mobile communication system employing a single carrier scheme for uplink and includes a scheduler configured to allocate radio resources such that a first control channel accompanying an uplink data channel is transmitted using the same frequency band allocated to the uplink data channel and a second control channel, which is to be transmitted regardless of presence or absence of the uplink data channel, is transmitted using a dedicated frequency band reserved for the second control channel if no frequency band is allocated to the uplink data channel; and a reporting unit configured to report scheduling information indicating the allocation results to a user device. The scheduler is configured not to allocate the radio resources to the uplink data channel of the user device in a unit transmission period reserved for transmission of the second control channel of the user device.