The purpose is to achieve accurate positioning without calculating an integer bias. A positioning device may include a positioning signal receiver, a triple phase difference calculating module, a triple phase difference adding module, and a positioning module. The positioning signal receiver may detect carrier phases of positioning signals from a plurality of positioning satellites. The triple phase difference calculating module may calculate a triple phase difference based on the carrier phases. The triple phase difference adding module may add the plurality of triple phase differences calculated in different periods. The positioning module may perform relative positioning using an added value of the triple phase differences as an observation value.