DRIVING ASSISTANCE DEVICE

A processor of an ECU includes a line-of-sight estimation unit that estimates a direction of a line of sight of a driver of a vehicle, a first looking-aside determination unit that determines whether the driver is looking aside, based on predetermined determination logic, when a line of sight of the driver is directed to a first looking-aside area deviating from a vehicle traveling direction, and a second looking-aside determination unit that determines whether the driver is looking aside, based on predetermined determination logic different from the predetermined determination logic of the first looking-aside determination unit, when a line of sight of the driver is directed to a second looking-aside area deviating from a vehicle traveling direction.