Parking assistance device

A parking assistance device for assisting in parking a towing vehicle and a towed vehicle to be towed by the towing vehicle when the towing vehicle and the towed vehicle are connected, the parking assistance device comprising:

• a parking start position acquiring unit configured to acquire a parking start position;
• a parking target position acquiring unit configured to acquire a parking target position;
• and
• a travel trajectory generation unit configured to generate a travel trajectory from the parking start position to the parking target position, wherein
• the travel trajectory includes a forward section in which forward movement is performed from the parking start position according to a set forward trajectory and a backward section in which backward movement is performed from a turning position set on the forward trajectory to the parking target position, and
• the travel trajectory generation unit
• sets a plurality of candidate turning positions on the forward trajectory of the towing vehicle in the forward section,
• calculates, for the respective plurality of candidate turning positions, travel trajectories of the towed vehicle as backward trajectories when the backward movement is assumed to be started from the candidate turning positions set on the forward trajectory of the towing vehicle, and
• compares the calculated backward trajectories of the towed vehicle for the respective plurality of candidate turning positions, and sets the turning position based on a comparison result.