A liquid sample is aspirated using an aspirating tube provided with a flow path extending lengthwise in the interior of the tube, and an aspiration orifice for aspirating the liquid sample formed near the tip of the tube. The aspiration of the liquid sample to the aspirating tube is monitored during aspiration. Liquid sample is aspirated by the aspirating tube, and the collected material in the aspirating tube in the region at the tip side from the region containing the liquid sample to be used for measurement is delivered to a detecting part provided externally to the aspirating tube, and whether or not liquid sample is contained in the collected material is detected in the detecting part.