In a case where a sample container 15 has a rubber-made lid 35, if a sample nozzle descends and comes into contact with the lid, the sample nozzle is relatively moved inside an arm as far as a lid detection distance, and a detector detects a detection plate. A fact that the sample nozzle comes into contact with the lid is stored together with position information of the sample nozzle, into an operation commanding unit. The sample nozzle further continues to descend, and a suction operation of a sample is performed at a predetermined position. In a case where the sample nozzle collides with a frame portion of the lid and external force is applied thereto, the detector detects that the detection plate is relatively moved as far as the detection distance.