It offers the best performance to quickly and accurately measure chloride ion concentrations contained in fresh concrete and aggregate. The chloride ISEs response to chloride ion in an aqueous solution selectively, and causes the difference of potential between ISEs and the reference electrode. All the calibration solutions, cleaning solutions, and sensors required for measurement are stored in the case for easy portability and use. From calibration to measurement to output, they are easy to operate. The measurement results can be checked in real time, and the self-diagnosis function is in the CPU so that the instrument status can be checked in real time and the user can immediately be notified in case of an error.