A wireless communication system has a transmitting device and a receiving device that perform communication by using a multi-carrier signal, wherein the receiving device includes a quality generating unit generating each piece of receiving quality information on each pilot channel for transmitting each pilot signal, a determining unit determining the number of pilot channels needed in the multi-carrier signal based on the receiving quality information, and a notifying unit transmitting a signal requesting the determined number of pilot channels to the transmitting device, and the transmitting device includes an allocation unit determining allocations of pilot signals in the direction of the time axis and in the direction of the frequency axis, corresponding to a requested number of pilot channels, and a transmitting unit transmitting the multi-carrier signal having the determined pilot signal allocations.