PURPOSE:To enable automatic dilution of a specimen while making effective use of the features of a direct system without providing an automatic mechanism for dilution, by subjecting operations for dilution to a sequence control sequentially on the basis of signals from a control element. CONSTITUTION:First, a sample cup 4A containing a urine specimen and an empty sample cup 4B for dilution in a pair are set in a plurality by the number of specimens on a turn table 2 in the circumferential direction alternately for each detection, and thereby a preliminary operation for measurement is completed. Next, an operation for dilution of the urine specimen is executed for each one specimen. The operation for dilution is executed by subjecting operations of elements to a sequence control sequentially on the basis of signals from a control element 15. Concretely, the operations of elements, such as rotary feeding for each one stop of the turn table 2, a rising-lowering operation at a position of suction-discharge of the specimen by a nozzle 6, operations for opening and closing three-way valves 7 and 8 and switching the directions thereof, the switching the number of rotations or the time of rotation of a roller pump 11 and the direction of a normal or reverse rotation, etc, can be executed automatically and sequentially under a sequence control at prescribed timings.