A control system includes: an input receiver that receives an input from a user; and a controller that, if a security system is set in a notification mode, brings the input receiver into a cancellation preparation state in response to a sensor being changed to a predetermined state. The notification mode is a mode in which a notification is provided after a predetermined time period has elapsed since the sensor has changed to the predetermined state. The cancellation preparation state is a state in which a cancellation input for cancelling a setting of the notification mode is receivable. The controller cancels the setting of the notification mode when the cancellation input is received by the input receiver in the cancellation preparation state.