A transmission device included in one base station in a radio communication system including communication areas adjacent to each other in which the base station communicates with a plurality of wireless terminals includes: a modulation unit that generates a data symbol sequence; a synchronization signal generating unit that generates a first symbol sequence constituted by two or more continuous repetitions of reference sequence symbols being a reference, generates a second symbol sequence by performing frequency shifting on the first symbol sequence by using a phase rotation sequence so that the reference sequence symbols become orthogonal for each of the wireless terminals, and generates a synchronization signal; and a synchronization signal adding unit that generates a transmission signal by adding the synchronization signal to the data symbol sequence.