Behavior prediction device

A behavior prediction device configured to predict behavior of another vehicle traveling around a host vehicle, the behavior prediction device comprising:

• a reference position setting unit configured to set a reference position along a shape of a road;
• a position detection unit configured to detect a position of the other vehicle;
• a distance calculation unit configured to calculate a distance from the reference position to the other vehicle on a basis of information about the reference position and information about the position of the other vehicle;
• and
• a prediction unit configured to predict a trajectory of the other vehicle on a basis of information about the distances in time series calculated by the distance calculation unit, wherein
• the prediction unit is configured to perform regression analysis by least squares method with respect to the information about the distances in time series calculated by the distance calculation unit, acquire a distance approximate expression including time and the distance as variables, and predict the trajectory by using the distance approximate expression,
• if the distance approximate expression expresses displacement of the other vehicle to one direction and if there is a three-dimensional object that is adjacent to a travel lane of the other vehicle in the one direction, the prediction unit is configured to correct the distance approximate expression by inverting the distance approximate expression by using, as an axis, a straight line that is parallel to a time axis on a coordinate plane including the time axis and a distance axis.