In order to report aperiodic channel state information (A-CSI) flexibly even when a user terminal performs radio communication using a plurality of component carriers (CCs) in an HetNet environment, the present invention provides an aperiodic channel sate information reporting method comprising: a step of transmitting in advance, from a pico base station (PeNB) to pico UE, channel state measurement target information having information about presence or absence of reporting of channel state information and a subframe as a measurement target associated with trigger bit information indicating information about presence or absence of reporting of channel state information and a component carrier as a measurement target (step ST401); and a step of reporting channel state information of the subframe and the component carrier designated by the trigger bit information transmitted on a PDCCH, to the pico base station (PeNB) on a PUSCH (step ST406).