Abstract: A rectangular-shaped holder containing sample solution is moved within a temperature adjusting box by a feeder. Then, the holder is moved by another feeder to the direction substantially perpendicular to the longitudinal direction of the holder by a length equal to the width of the single holder. The holders thus sequentially fed within the temperature adjusting box are disposed within the box in a closely contacted state from one another. There are three holders within the temperature adjusting box in advance and four holders are stayed within the box. Rectangular-shaped four heaters are disposed within the temperature adjusting box such that the heating temperature thereof is controlled by a temperature adjusting controller. A compensation heater controlled by a temperature compensating controller compensates for a heat quantity shifted to the holder having been newly housed within the temperature adjusting box from the holders already housed within the temperature adjusting box.