Provided are a leak inspection assistance device and a leak inspection method using the same which enable using a normal leak inspection device in a leak inspection of filters in a clean room, have a small cost burden since a scanning robot, large-scape equipment, an incidental work, and the like are not required, and enable performing the accurate leak inspection with a small number of workers.A projection device which projects a suction point of a suction probe adjunct to a leak inspection device which performs a leak inspection onto a surface of a filter in a clean room in such a manner that the suction point moves in X-Y axis directions orthogonal to each other along the surface of the filter at a fixed interval and a fixed speed is provided, and a worker uses the suction probe for scanning in accordance with movement of the suction point.