This invention discloses a spectacle edging assist device including a flexible layout chart, chart holding portion, and spectacle frame holding portion. An index used to determine the suitability of a lens while the layout chart is superposed on a spectacle frame is drawn on the flexible layout chart. The chart holding portion holds the layout chart upon bending the layout chart to have a curvature corresponding to the frame curve of the spectacle frame, and also holds the layout chart to be movable in the horizontal direction of the spectacle frame. The spectacle frame holding portion holds the spectacle frame so that its front portion overlaps the layout chart. The chart holding portion brings at least two end pieces of the spectacle frame into contact with the layout chart. A spectacle lens suitability determining method is also disclosed.