The present invention is designed to minimize the increase of user terminal power consumption even when downlink control channels are extended. A radio base station apparatus having: an allocation section that allocates downlink control information in a first control region from a top of a radio frame to a predetermined OFDM symbol and in a second control region that is frequency-divided with a data region in a region that is time-divided with the first control region, and also allocates decoding control information that indicates a user terminal to perform a decoding process for the second control region, in the first control region; and a transmission section that transmits the downlink control information and the decoding control information; and a user terminal having: a receiving section that receives the downlink control information and the decoding control information from the radio base station apparatus; and a decoding section that controls the decoding process for the second control region based on the decoding control information received, are provided.