TRAVEL CONTROL DEVICE, TRAVEL CONTROL METHOD, AND STORAGE MEDIUM STORING TRAVEL CONTROL PROGRAM

A travel control device is configured to execute: a coasting travel process; a cruise travel process, a gradient information acquisition process acquiring, as gradient information, information indicating a gradient of a road surface on which a vehicle is traveling; a deviation variable acquisition process acquiring a deviation variable for determining an acceleration generated in the vehicle when the vehicle travels, by performing the coasting travel process, a downward slope having a predetermined gradient; and a switching process using the gradient information and the deviation variable as inputs and performing switching to the coasting travel process according to a value of the deviation variable even though a magnitude of the gradient of the road surface is different from a reference value.