PURPOSE: To obtain an apparatus which enables the saving of a reaction tube cleaning liquid preventing mixing of reagents by arranging reaction tubes equivalent to multiplying N integral times on one reaction line, a detector section for detecting the intermittent movement of the reaction tubes N at a time and specialized distribution nozzles for N types of reagents.

CONSTITUTION: Reaction tubes, for example, numbering 216 equivalent to multiplying 8 eight times are arranged at an equal space on an endless timing belt 1 and can be moved intermittently at an equal speed with a drive pulley 2a and a driver pulley 2b. The movement of a belt 4a running between the pulley 2a and a first detector section 4 is detected and a movement detection signal (a) for each step of the reaction tubes 13 is outputted to a control section 8 of a test piece nozzle 6. On the other hand, a second detector 5 counts signals of the detector 4 and outputs detection signal (b) 8 steps at a time to nozzle control sections 10aW10h so that reagents are each put into specific reaction tubes 3 with nozzles 9aW9h from reagent containers 10aW10h. Then, after a photometry with a measuring section 1b, the reaction tubes 13 are cleaned with a cleaning section 1C.