An automatic analysis device includes a processing unit 3 which performs the treatment on a specimen before analysis of the specimen, supply equipment which supplies a reagent to a reaction vessel 11 disposed in the processing unit 3, a liquid temperature adjusting unit 1 which adjusts a temperature of the reagent supplied to the reaction vessel 11 by the supply equipment, a control unit 201, and a first temperature detection unit 4 which detects at least one temperature of a temperature of the air within the processing unit 3 and a temperature of the reagent supplied to the reaction vessel 11, in which the liquid temperature adjusting unit 1 and the control unit 201 execute temperature adjustment of the reagent based on a first temperature detected by the first temperature detection unit 4.