Measurement instruments specialized for measuring and monitoring noise levels in manufacturing environments. Supports safety management of work environments and compliance with noise regulations through quantitative measurement of machine operation sounds, processing sounds, and equipment noise in factories. Includes digital sound level meters, precision sound level meters, sound level meters with data logger functions, and models equipped with frequency analysis capabilities, enabling measurement in dB(A) and dB(C). Essential equipment for noise evaluation during manufacturing line design, abnormal sound detection in equipment maintenance, and regulatory compliance in work environment measurement, clearly distinguished from vibration measurement instruments by measurement targets.