The purpose of the present invention is to provide an automatic analysis device capable of determining, through a simple processing, whether or not idle aspirate has occurred. The automatic analysis device according to the present invention determines whether or not idle aspirate has occurred, by calculating a parameter which specifies whether or not the length of a portion of a path through which the sample passes inside a dispensing probe is shorter than that during normal aspirate, the portion being actually filled with a sample (see FIG. 4).