PURPOSE: To reduce the misreading, by moving respective containers with a sample identification code attached thereto after the reading of the first code to perform the reading of the second code.

CONSTITUTION: A sample container 10 is shifted rotatively together with a table 14 and stopped temporarily by a desired distance before. A sample identifier 16 is operated and a bar code reader is lifted to read out the code of a label 12 while standing by at the upper dead point. Data are memorized into a memory 17. Then, a table 14 turns by a specified distance and stops at the sampling position. The sample identifier 16 is operated again and the bar code reader is lowered to read out the bar code again while stops at the lower dead point until the subsequent container 10 comes. The data read again is compared with the data previously memorized and when they are equal, the operation shifts to the subsequent cycle but when they are difference, an alarm processing is done.