Abstract: A ruler having an arch member on an upper surface of a ruler body for allowing the ruler body to closely contact a target object by being pressed from above. The ruler has a pair of parallel standing walls facing each other on the upper surface of the ruler body in a longitudinal direction, and the arch member is fitted along the longitudinal direction of the standing walls. In addition, bending pieces which bend inward towards each other are formed on upper end edges of the standing walls, projections which are positioned below the bending pieces project on both of outer side surfaces of the arch member, and the projections are guided by the bending pieces and are inserted between the standing walls.

Abstract: There has been no ruler having an arch member on an upper surface as in related art, which is suitable for mass production to reduce the price and can be formed by using different materials for a ruler body and the arch member, and in which there is no backlash and edges for operations of the ruler body closely contact a surface of a target object so as not to move.

Abstract: A ruler in which one pair of parallel cuts are put in one raw material plate, a supporting point part is formed by narrowing both ends of the parallel cuts or making the both ends like a fork, a bent cut or a linear cut reaching to an end part of the raw material plate is put so as to surround the supporting point part or extend along it, and an arch part, in which a part included between the parallel cuts is bulged upward by heating, pressure friction, injection molding or chemical treating, is formed monolithically with the raw material plate, or made one in which a slip stop is applied wholly or partially in a back face of the arch part.