A radio base station and a mobile communication system where a hand-over request is detected and retransmission data is preferentially processed for a hand-over object terminal. A radio base station may include a buffer holding communication data for transmission to a terminal, an extractor extracting a communication request signal from a received signal, and a scheduler controlling transmission of the communication data based on an output signal of the extractor. Also a scheduler, upon detection of a hand-over request, controls transmission so as to preferentially perform the data transmission by raising an order of the data transmission for a hand-over terminal before hand-over.