A parking assistance device includes at least one electronic control unit configured to execute parking assistance according to an operation from a user, such that a vehicle is automatically parked at a target position. The at least one electronic control unit is configured to determine whether or not the vehicle is in a predetermined environment which is darker than a predetermined brightness level. The at least one electronic control unit is configured to, when the at least one electronic control unit determines that the vehicle is in the predetermined environment, control a lighting device which is provided in the vehicle such that the lighting device is lighted without performing lighting with a high beam, while the parking assistance is executed.