An automatic chemical analyzer in which a reaction solution is stirred by air ejected from an air ejection hole placed above a reaction container. The reaction region can be washed and cleaned sufficiently without causing damage, such as exfoliation of a coating reagent. A reaction container disk is provided with a pore and a pressure detector connected with the pore. Before and after the stirring operation, the ejection hole (nozzle) ejecting air is moved and the output value of the pressure detector is compared with a previously measured normal value. With a discharge pipe and a suction pipe inserted to the opening of the reaction container to be close to both ends of the opening and the side wall of the container, the reaction region at the bottom of the container is washed by continuous discharge and suction of cleaning fluid.