A non-interdependent displacement measuring device for converting a rotary motion to a linear motion is disclosed, which includes a driving unit, a detection unit, and a resistance device. The driving unit includes an adjustment section and a driving section. The detection unit is arranged in the adjustment section. The driving section is connected to the resistance device. The detection unit includes a sensing module and a transmission module, and the detection unit is arranged in the adjustment section, so that when the adjustment section rotates, the detection unit detects turns and an angle of rotation of the adjustment section to generate a detection signal, which, after being subjected to calculation, is transmitted through the transmission module to the electronic device to display the level of an resistance, so as to overcome the drawbacks of the prior art that accuracy is poor, calibration is difficult, and fabrication is difficult due to a magnet and a sensor being arranged as two separate parts.