The utility model discloses a but adjusting gauge, including body (1), screw (2), percentage table (3) and gauge head (4), the arched bridge shape of handle is taken for the bottom in body (1), and open at body (1) arched bridge shape both ends top has the crack, and the pinhole is beaten at both ends around the body, and the pinhole communicates with each other with pressing from both sides the calking, and the fix with screw is passed through respectively in the pinhole at both ends in gauge head (4) and percentage table (3), measuring point between gauge head (4) and percentage table (3) leaves the vacancy, makes the measurand product put into the body. The utility model discloses can effectively record the error of the product that is not conform to the requirement, improve accuracy and work efficiency, have simple structure, with low costs, effect that the precision is high. The utility model discloses a gauge head is adjustable, can be used for comparing of not unidimensional work piece.