Parking assistance device

A parking assistance device that displays, on a display device, a captured image obtained by an imaging device included in a vehicle imaging surroundings of the vehicle, and

• in a case where a parking slot that is a candidate for a parking target position where the vehicle is parked is detected, displays a target parking space image indicating that the parking slot in the captured image is a candidate for the parking target position,
• wherein a process of displaying the target parking space image includes
• detecting, in a case where the parking slot for which the target parking space image is displayed is located on a side of a passage through which the vehicle travels, an angle of a boundary between the parking slot and the passage,
• determining an angle at which the target parking space image displayed for the parking slot is displayed based on the detected angle of the boundary, and
• displaying the target parking space image at the determined angle.