The invention discloses a resistance measuring instrument. The resistance measuring instrument comprises a measurement system for measuring products, a feeding system for feeding the measurement system so that products are measured by the measurement system and an overall integration part for overall coordination of the feeding, measuring and selecting; the overall integration part comprises a control system and a controlled part; the control system is electrically connected with the controlled part; the controlled part comprises a first cylinder which guarantees that only one part to be measured is in the position of a measurement head part at one time, a second cylinder which is used for realize front and back operation of the measurement head to complete measurement, a third cylinder which is used for selecting and classifying measured parts, a material control part which is used for controlling the flow of measured parts and the measurement head part which is used for detecting theresistance of parts to be measured. By using this resistance measuring instrument, the resistance of measured parts can be measured automatically, which avoids wasting labor force, increases the measuring efficiency of the measured parts and reduces the measuring cost.