PURPOSE: To take an in-line analysis by installing a sample cell in the middle of branch pipes which return a sample after the sample is sampled from piping where the sample to be analyzed flows and analyzed.

CONSTITUTION: A solution 1 to be analyzed is nuclear matter used in nuclear power facilities, etc., and flow in the piping 4 installed in a chamber 3 partitioned by a wall 2 which has the ability to cut off radiation. This device employs an in-line system where in the solution 1 is never taken out of the piping 4 and returned to the piping 4 after a concentration analysis is taken, so branch pipes 61 and 62 are provided so that the solution 1 is guided from the piping 4 to the sample cell 5 at an analytical position and returned to the piping 4 again. Exciting light is made incident on the sample cell 5 to obtain surface fluorescent light from the incidence surface, flank fluorescent light from the flank, and transmitted light for absorption analysis from a surface passing through the sample, thereby selecting those analytic light beams according to the state of the sample.