Thermal cycler and control method of thermal cycler

A thermal cycler comprising:

• an attachment unit for attachment of a reaction container including a channel filled with a reaction solution containing hot start PCR enzyme and a liquid having a specific gravity different from that of the reaction solution and being immiscible with the reaction solution, the reaction solution moving close to opposed inner walls;
• a first heating unit that heats a first region of the channel when the reaction container is attached to the attachment unit;
• a second heating unit that heats a second region of the channel different from the first region when the reaction container is attached to the attachment unit;
• a drive mechanism that switches arrangement of the attachment unit, the first heating unit, and the second heating unit between a first arrangement in which a lowermost position of the channel in a direction in which gravity acts is located within the first region and a second arrangement in which the lowermost position of the channel in the direction in which the gravity acts is located within the second region when the reaction container is attached to the attachment unit;
• and
• a control unit that controls the drive mechanism, the first heating unit, and the second heating unit,
• wherein the control unit performs
• first processing of controlling the first heating unit at a first temperature,
• second processing of controlling the second heating unit at a second temperature higher than the first temperature,
• third processing of allowing a first period to elapse with the arrangement of the attachment unit, the first heating unit, and the second heating unit being the second arrangement after the second processing, and
• fourth processing of controlling the drive mechanism to switch the arrangement of the attachment unit, the first heating unit, and the second heating unit from the second arrangement to the first arrangement if a second period has elapsed with the arrangement of the attachment unit, the first heating unit, and the second heating unit being the second arrangement after the first processing and the third processing.