A thermal cycler includes an attachment unit having an insertion opening for insertion of a reaction container including a channel filled with a reaction solution containing reverse transcriptase enzyme and a liquid having a lower specific gravity than that of the reaction solution and being immiscible with the reaction solution, a first heating unit that heats a first region of the channel, a second heating unit that heats a second region of the channel nearer the insertion opening than the first region, a drive mechanism that switches arrangement of the attachment unit, the first heating unit, and the second heating unit between a first arrangement and a second arrangement, and a control unit that controls the first heating unit to be at a temperature at which reverse transcription reaction progresses and the second heating unit to be at a temperature at which the reverse transcriptase enzyme is not deactivated.