Data logger for measurement device

A data logger to be used for a measurement device that measures a mass of an object, comprising:

• a data logger main body including a main body case;
• a temperature sensor;
• a humidity sensor;
• and
• an air pressure sensor and an acceleration sensor, the sensors serving as an environmental sensor that detects a physical quality of an environment where the measurement device is installed, wherein
• the humidity sensor and the temperature sensor are configured as a temperature/humidity sensor unit that includes a sensor case formed in a rectangular-parallelepiped shape and attachable to and detachable from the data logger main body that incorporates the air pressure sensor and the acceleration sensor, a data memory, and a CPU, and the temperature/humidity sensor unit includes a temperature/humidity data output terminal to transmit data to the data logger main body,
• the data logger main body case comprises a temperature/humidity terminal connector connectable with the temperature/humidity data output terminal;
• and a temperature/humidity sensor unit housing recess portion that is substantially complementary in shape to the sensor case of the temperature/humidity sensor unit so as to receive and store the sensor case,
• wherein the temperature/humidity sensor unit is integrated in external appearance with the data logger main body by connecting the temperature/humidity data output terminal to the temperature/humidity terminal connector.