CONTROLLER AND CONTROL METHOD FOR VEHICLE

A vehicle includes an accelerator sensor, a vehicle speed sensor, and a gradient sensor. A controller for the vehicle is configured to execute a calculating process that calculates a traveling driving force required to move the vehicle forward based on a vehicle speed and an operation amount of an accelerator pedal, and a cruise control process that controls the vehicle speed such that the vehicle speed becomes a constant target vehicle speed. The controller is configured to execute the cruise control process on condition that a difference between a maximum value and a minimum value of the vehicle speed within a specified time period is less than or equal to a specified value, and a sum of a traveling resistance calculated based on the vehicle speed and a gradient resistance calculated based on the gradient of the road surface is greater than or equal to the traveling driving force.