PURPOSE: To detect a more accurate chemical analysis value by continuously carrying out the intermittent feed of an analytical slide by a feed mechanism part to make the random access of the analytical slide possible.

CONSTITUTION: When the time required in rotating the disc 6 of a feed mechanism part B over the distance corresponding to one side receiving part 6a is set to Td and the tolerant error to the end point reaction time from the dripping of a sample to photometry is set to IDT, in such a case that only one empty slide receiving part 6a is present on the disc 6, a dripping shutter 3 is opened before the 2DT point of time from the point of time when the empty slide receiving part 6a is moved from a dripping position and closed before the elapse of the time Ti required in inserting an analytical slide in the disc 6 from said point of time. That is, when the empty slide receiving part 6a reaches the front of the slide receiving part 6a of a dripping mechanism part B, the dripping shutter 3 is opened and, before the point of time when the empty slide receiving part 6a moves from the dripping position, the shutter 3 is closed.