Remote meter reading terminal devices 2 generate electronic signature data based on meter reading information that includes a measured value acquired by electricity meters 3, measurement date and time, and an electricity meter ID, and transmit the generated electronic signature data and the meter reading information to a meter reading data management server 1. When the verification of the electronic signature data received from the remote meter reading terminal devices 2 has succeeded, the meter reading data management server 1 generates a hash value of the meter reading information and transmits the generated hash value to a TSA server 4. The meter reading data management server 1 also acquires a time stamp generated by the TSA server 4 and stores therein meter reading data that includes the time stamp, the meter reading information, the electronic signature data and the hash value.