An immunoassay apparatus may include: a sample dispenser part that dispenses a sample into a first reaction container; a reagent dispenser part that dispenses, into the first reaction container: a solid-phase reagent containing a solid-phase carrier; a labeled reagent; and a releasing reagent that releases, from the solid-phase carrier, an immune complex including a target substance and a labeled substance; a measurement part that measures a signal based on the labeled substance in the immune complex in a second reaction container; a container supply part that stores a plurality of reaction containers; a transfer part that transfers the first reaction container so that the sample dispenser part and the reagent dispenser part perform a dispensing operation to the first reaction container, and that transfers the second reaction container so that the immune complex dispended from the first reaction container is dispensed into the second container.