MOTORCYCLE DRIVING ASSISTANCE DEVICE

A motorcycle driving assistance device includes: a curve traveling determination unit for determining whether or not an own vehicle is traveling on a curve; a radius-of-curvature calculation unit for, when it is determined that the own vehicle is traveling on a curve, calculating a radius of curvature of the curve; an other-vehicle lane estimation unit for comparing the radius of curvature and a distance between another vehicle and a center of curvature of the curve, and estimating a traveling lane of the other vehicle; and an alarm determination unit for determining whether or not output of an approach alarm is needed, on the basis of a distance between the own vehicle and the other vehicle, a relative velocity of the other vehicle, and a relationship between a traveling lane of the own vehicle and the traveling lane of the other vehicle.