TRAVEL CONTROLLER AND TRAVEL CONTROL METHOD

A travel controller determines whether a traveling lane in which a vehicle is traveling is a merged lane into which a merging lane merges using peripheral data that represents a surrounding situation of the vehicle, and while the traveling lane is the merged lane, repeatedly performs yielding determination to detect a merging vehicle traveling in the merging lane from the peripheral data, and to determine whether or not yielding control for securing a larger space for the merging vehicle to change the lane to the merged lane is necessary, the yielding determination at the first time being performed based on a relative positional relationship between the merging vehicle and the vehicle, the yielding determinations at the second and subsequent times being performed based at least on a result of a previous yielding determination, and controls travel of the vehicle according to the result of the yielding determination.