The present invention is designed to provide a wireless communication system, a base station apparatus, a user terminal, and a channel state information measurement method that can allow a user terminal to feed back channel quality information that is optimal for a transmission mode from a plurality of transmission points. A wireless communication system according to the present invention provides a base station apparatus having a determining section that determines resource information about resources to allocate the reference signal for measuring desired signals to, and resource for measuring interference signals, and a reporting section that reports the resource information to the user terminal, and the user terminal having a receiving section that receives the reported resource information, a measurement section that measures desired signals and interference signals based on the resource information, and a measurement section that measures the channel state using the measurement results of the measurement section.