There is a concern that in the case of performing stirring by the discharge pressure of a reagent or a sample, a mixing ratio of the sample to the reagent varies, and therefore, stirring cannot be sufficiently performed at a constant discharge speed, and thus, a reaction occurs non-uniformly. On the other hand, if the discharge speed is increased excessively, foaming occurs, resulting in disturbing the measurement of a change in light intensity. A control section causes one dispensing mechanism of either a reagent dispensing mechanism or a sample dispensing mechanism to first discharge a predetermined amount of a liquid into the reaction container, and then, with respect to the cases where the amount of a liquid to be discharged by the other dispensing mechanism is larger or smaller than the amount of the liquid in the reaction container, causes the other dispensing mechanism to discharge the liquid such that the discharge speed in the case where the amount of the liquid to be discharged is larger is decreased relative to the discharge speed in the case where the amount of the liquid to be discharged is smaller.