A PCR device, in which a vessel is filled with a liquid which has a lower specific gravity than a reaction mixture and is immiscible with the reaction mixture, and a control section drives and controls a first heating section and a second heating section so that the liquid in an upper part in the vessel is brought to a first temperature and the liquid in a lower part is brought to a second temperature which is lower than the first temperature, and also drives and controls an electric field generation section to generate an electric field between a lower electrode and an upper electrode so that the reaction mixture in a spherical shape in the liquid moves up and down repeatedly between the upper part and the lower part of the liquid by a Coulomb force due to the electric field.