Parking Assistance Method and Parking Assistance Device

A parking assistance method for assisting parking of an own vehicle at a target parking position includes: permitting, in a case where when accepting, while having selected one mode of a first assistance mode for assisting parking with a pre-registered parking position candidate set as the target parking position and a second assistance mode for assisting parking with the target parking position set without using a pre-registered parking position candidate, a switching instruction to the other mode, the own vehicle is stopping, switching from the one mode to the other mode; and not permitting, in a case where when accepting the switching instruction, the own vehicle is not stopping, switching from the one mode to the other mode.