To provide an automatic chemical analyzer capable of preventing the malfunction by noise of a sucking and discharging operation when a liquid quantity in a sample vessel is very small and precisely performing the suction and discharge to realize a sampling with high measurement precision or reliability.

This device comprises the housing vessel for housing a subject sample and a sampler for arranging the sample vessel. A probe is vertically and horizontally moved by an arm to suck the sample. An arrangement position for the sample vessel housing a trace subject sample is provided on the inside or outside of the sampler. Accordingly, since the exclusive arrangement position for the subject sample, when its quantity is very small, can be discriminated, a malfunction by noise, for example, can be prevented to provide a device with high measurement precision and reliability.