A gate system control device is a gate system control device configured to control a gate system having an exit gate, and includes a first sensor, a second sensor, and a controller. The first sensor senses that a passport of a person who is in the gate system is placed on a placement region. The second sensor senses that the person is moving. The controller controls the gate system. When the first sensor senses that the passport is placed on the placement region and the second sensor senses that the person is moving to the exit gate, the controller causes the gate system to execute processing for notifying the person.