PURPOSE: To secure high accuracy of an organismic fluid assaying device and to automate the operation of the device without inviting any error by providing an introduction magazine for plate supporting bodies and a discharge magazine for accepting the supporting bodies after the supporting bodies pass through various operation stations.

CONSTITUTION: The organismic fluid assaying device is provided with a microprocessor M to which test information is inputted, a plurality of individual plate supporting plates 11, and an introduction magazine 10 and a discharge magazine 13 for the supporting bodies 11. The device is also provided with many operation stations, such as a transfer station, etc., between the magazines 10 and 13 and a plate supporting body carrying means which is controlled by means of the microprocessor M so as to collect the supporting bodies 11 from the magazine 10 and send the bodies 11 to the magazine 13 after successively carrying the bodies 11 through the operation stations. Since the carrying means is provided with a means which reads labels 18 and 28, the microprocessor M can confirm that each supporting body 11 taken out from the magazine 10 is properly selected and loaded and, at the same time, can confirm the effectiveness of other movement of each supporting body 11 in assay cycles.