Provided is a technique related to an automatic analyzer and capable of ensuring cleaning performance of a reaction container by a cleaning process including a tip suction step, and preventing decrease in analysis accuracy or improving the analysis accuracy. The automatic analyzer includes a control apparatus, a block suction mechanism that moves a suction nozzle and a suction block for suctioning a liquid in the reaction container up and down and suctions the liquid, and a block cleaning mechanism for cleaning the suction block. After receiving an analysis request, the control apparatus causes, in a tip suction step that is provided before an analysis step and is a last step of a cleaning step, both suction of the liquid by the block suction mechanism and cleaning of the suction block by the block cleaning mechanism to be performed in a first step, and then only the suction of the liquid by the block suction mechanism to be performed in a second step including one or more cycles; and causes the analysis step to be performed using the reaction container in which the second step is performed.