A wireless communication system which enables fast handovers by eliminating a time lag that occurs during handover process. A new base station recognizes lower layer link switching timing of a mobile station, then adjusts the output timing of a packet transmission initiation message, which triggers packet transmission, so that when a packet is transmitted from a new relay device to the mobile station, the packet may arrive at the mobile station immediately after the lower layer link switching, and sends out the packet transmission initiation message at the adjusted output timing to the new relay device. On receiving the packet transmission initiation message, the new relay device transmits the packet to the mobile station. The mobile station executes the lower layer link switching to complete lower layer handover, and then completes upper layer handover on receiving the packet from the new relay device immediately after the link switching.