PROBLEM TO BE SOLVED: To provide an opening/closing control system for a gateway, which identifies a pet and which can control opening/closing of a gateway according to a keepers intention.SOLUTION: When an ID number of a microchip 32 attached to a pet 14 is read by an outdoor-side reader 34B, notification for inquiring whether or not a door 18 for the pet is opened is given to a customer terminal 50 of a customer H. The customer H determines whether or not the door may be opened. When the customer H transmits an opening signal from the customer terminal 50, the automatic door 18 for the pet is opened.
