Provided is a moisture meter including a mass measurement unit for measuring the mass of a specimen, a heater for heating the specimen, a control arithmetic unit configured to control the heating unit to heat the specimen until a change in the mass of the specimen becomes not more than a predetermined threshold and calculate the moisture content of the specimen, a timepiece for measuring a heating time, and a storage unit. The control arithmetic unit measures the moisture content of a standard substance for inspection and a heating time, diagnoses the presence/absence of an abnormality in the heating unit by comparing a measured heating time with a predetermined time as a set heating time stored in the storage unit in advance.