AUTOMATIC ANALYSIS DEVICE

To provide an automatic analyzer without necessity of manual air vent in a pump.An automatic analyzer comprises a water supply tank 53, a supply path 70 connected to each mechanism of an automatic analyzer 100 from the water supply tank 53, a water supply pump 54 which supplies water to each mechanism from the water supply tank 53 through the supply path 70, a detector 61 which detects abnormality in the supply path 70, a waste liquid path 63 branched from the supply path 70 in a branch pipe 60 provided in the supply path 70, a relief valve 62 provided in the waste liquid path 63, and a control unit 64 which controls the operation of each mechanism in the automatic analyzer 100, in which the control unit 64 opens the relief valve 62 while driving the water supply pump 54, based on the abnormality in the supply path 70 detected by the detector 61.