A display shelf track device has a downwardly protruding member for attaching the track device to the shelf. The trench with a smaller opening width is formed so as to have a first depth and the trench with a larger opening width has a bottom including opposite ends each of which has a second depth deeper than the first depth and a central portion shallower than the second depth. The projections 5 and the joints 4 are arranged such that the projections and the joints alternate in one direction to make lines and that the projections in each of the lines are out of alignment with the projections in the adjacent lines.