The utility model discloses a single round range finding instrument, including the connecting rod, the one end of connecting rod is equipped with the handle, being equipped with count display device on hand, the one end that the handle was kept away from to the connecting rod is equipped with the shaft, the outside equidistance of shaft is encircleed and is equipped with a plurality of connecting pieces, one side that the shaft was kept away from to the connecting piece is equipped with the measuring wheel circle, the surface of measuring wheel circle is equipped with the scale mark, one side that the measuring wheel circle is close to the connecting rod is equipped with a infrared sensing devices, and is equipped with the 2nd infrared sensing devices who corresponds with a infrared sensing devices position on the connecting rod, the middle part of connecting rod is equipped with the bracing piece perpendicularly, the one end that the connecting rod was kept away from to the bracing piece is equipped with the pull rod, the lower extreme of pull rod is equipped with the leading wheel, and this utility model structure is simple, and not only artifical measuring error nature has been avoided to effectual survey track, has improved the accuracy of range finding, has reduced the cost of goods and materials transportations, practicality very.