A moisture meter comprising: a mass measurement unit configured to measure a mass of a specimen placed on a weighing dish; a heating chamber having the weighing dish placed inside and configured to open and close; a heating unit placed in the heating chamber and configured to heat the specimen; a control arithmetic unit configured to control the heating unit to heat the specimen until a change in mass of the specimen becomes not more than a predetermined threshold and calculate a moisture content of the specimen from the change in the mass of the specimen before and after heating; a timepiece configured to measure a heating time; and a storage unit, wherein the heating unit includes a heating means, the heating chamber includes a glass cover to prevent the specimen from coming into contact with the heating means, the control arithmetic unit includes a standard substance measurement unit configured to measure a moisture content of a standard substance for inspection as the specimen and measure a heating time, and an abnormality diagnosis unit configured to diagnose presence or absence of an abnormality in the mass measurement unit by evaluating whether the measured moisture content falls within a predetermined range with reference to a theoretical moisture content of the standard substance, and wherein the standard substance has a known theoretical moisture content and a known appropriate heating temperature for a measurement of moisture content, characterized in that the storage unit stores, as a set heating time, a heating time that is calculated when a moisture content of the standard substance is measured when heated at the appropriate heating temperatures, the abnormality diagnosis unit is configured to diagnose presence or absence of an abnormality in the heating unit by comparing a measured heating time with a predetermined time as the set heating time stored in the storage unit, wherein the abnormality diagnosis unit determines that there is an abnormality in the heating unit when the measured heating time is longer than the predetermined time, and wherein the determined abnormality is contamination on the glass cover or contamination on the heating means. a mass measurement unit configured to measure a mass of a specimen placed on a weighing dish; a heating chamber having the weighing dish placed inside and configured to open and close; a heating unit placed in the heating chamber and configured to heat the specimen; a control arithmetic unit configured to control the heating unit to heat the specimen until a change in mass of the specimen becomes not more than a predetermined threshold and calculate a moisture content of the specimen from the change in the mass of the specimen before and after heating; a timepiece configured to measure a heating time; and a storage unit, wherein the heating unit includes a heating means, the heating chamber includes a glass cover to prevent the specimen from coming into contact with the heating means, the control arithmetic unit includes a standard substance measurement unit configured to measure a moisture content of a standard substance for inspection as the specimen and measure a heating time, and an abnormality diagnosis unit configured to diagnose presence or absence of an abnormality in the mass measurement unit by evaluating whether the measured moisture content falls within a predetermined range with reference to a theoretical moisture content of the standard substance, and wherein the standard substance has a known theoretical moisture content and a known appropriate heating temperature for a measurement of moisture content, characterized in that the storage unit stores, as a set heating time, a heating time that is calculated when a moisture content of the standard substance is measured when heated at the appropriate heating temperatures, the abnormality diagnosis unit is configured to diagnose presence or absence of an abnormality in the heating unit by comparing a measured heating time with a predetermined time as the set heating time stored in the storage unit, wherein the abnormality diagnosis unit determines that there is an abnormality in the heating unit when the measured heating time is longer than the predetermined time, and wherein the determined abnormality is contamination on the glass cover or contamination on the heating means.