Travel controller and method for travel control

A travel controller detects, from an image representing the face of a driver of a vehicle, an act of the driver checking surroundings of the vehicle, records a time at which the act of checking is detected, and suggests to the driver a lane change for the vehicle to change a travel lane to an adjoining lane. In the case that the act of checking is detected in a precheck period before a suggestion time at which the lane change is suggested, the travel controller makes the vehicle execute the lane change regardless of whether the act of checking is detected in a post-suggestion check period after the suggestion time of the lane change.