To provide an automatic analyzer which is not influenced by fluidity or viscosity of a sample, and which can stably dispense the sample with dispensing accuracy by determining whether a flow route including a sample probe is in a stable and suction-available state when the sample is suctioned. In suction of the sample, before the sample is suctioned, in the flow route including the sample probe, the automatic analyzer determines whether the sample is in a suction-available state or in a suction-unavailable state, and performs cleaning on the flow route when it is determined that the sample is not in the suction-available state. Since the state in the flow route including the sample probe is determined before the sample is suctioned, the automatic analyzer can repeatedly perform a dispensing operation having improved reliability, without being influenced by the fluidity or the viscosity.