The utility model discloses an off -axial single bond symmetry measuring device, including measuring device body and locating piece, the locating piece sets up the horizontal pole lower part of body clamps the single bond inslot at the volume of awaiting measuring work piece during the one end measurement, the montant middle part of body is connected with the percentage table, the top of percentage table is connected with the gauge head of cylinder type structure, the gauge head with the work piece contact is used for carrying on the symmetry and measures. Adopt with the work piece groove width matched with locating piece of process, the card advances the single bond inslot as whole measuring device's location benchmark, fix a position that accurate reliably the gauge head on the use percentage table and the face of cylinder coordinates, the gauge head of being convenient for can touch the peak of this section excircle of work piece, the influence of negligible this section excircle circularity and straightness accuracy error.