A control method includes acquiring time information including a wake-up set time; acquiring a sleep state of a sleeper who is stimulated by a stimulation device; determining a change of the sleep state; causing the stimulation device to start increasing a stimulus which urges the sleeper to awake at a control start time as time before the wake-up set time by a predetermined time period; and controlling a change amount of the stimulus based on the change of the sleep state with the stimulus.