Accurate waistline measuring device

The invention discloses an accurate waistline measuring device. According to the technical scheme, the accurate waistline measuring device comprises a rack and a surveying and mapping pen, wherein therack is slidably connected with a sliding seat in the vertical direction; the sliding seat is detachably connected with a fixing rod; an end of the fixing rod is connected with a protecting box; theinside of the protecting box is rotatably connected with a reel; a torsional spring sleeves the outside of the rotating shaft of the reel; the other end of the torsional spring is fixed in the protecting box; the reel is wound with a strip coil; one end of the strip coil is fixed on the reel; the surveying and mapping pen is fixed at the other end of the strip coil; a positioning portion for positioning a surveying and mapping point is further arranged on the sliding seat; and the rack is further provided with a control portion which is used for controlling the strip coil not to float up and down when the strip coil is