An apparatus for automatically performing a sandwich-type enzyme immunoassay. The apparatus includes a rack for holding test tubes. In the test tubes are beads which provide surfaces for the immuochemical reactions. The rack can be moved in lengthwise and transverse directions. Nozzles for supplying and withdrawing liquids from the test tubes are included. The bead in one tube can be transferred to a second tube. The absorbance of a final liquid is measured spectrophotometrically, and the results are recorded by a printer.