A wireless base station (eNB) is provided with a decision unit (14) that is configured to determine the number of assignable OFDM symbols that indicate the number of OFDM symbols in each sub-carrier that can be assigned to the control channel in a downlink, for individual sub-frames that are configured with a prescribed number of OFDM symbols. The decision unit (14) is configured to calculate the number of OFDM symbols corresponding to the communication conditions in each sub-frame in a measurement interval and to set the maximum number of the calculated number of OFDM symbols as the number of assignable OFDM symbols in each-subframe in the next control interval that will start after completion of the measurement interval.
