A delivery server includes: a reception unit of receiving meter indication data of an existing gas meter and meter indication data of a new gas meter from a mobile terminal; a modification unit causing the new gas meter to be managed as a gas meter to be managed that is installed in a supply facility; and a meter reading processing unit performing a gas meter reading processing for the supply facility, when meter indication data of the new gas meter on a current meter indication date from the mobile terminal after gas meter replacement, on the basis of the received meter indication data, respective meter indication data of the new gas meter and the existing gas meter in the gas meter replacement, and meter indication data of the existing gas meter in the supply facility on a previous meter indication date of earlier than the gas meter replacement.