PURPOSE: To eliminate a variation in a resistance value of a rotary operation type variable resistor due to an impact, a vibration, etc., and to obtain a high rotary torque by providing a protrusion in contact with the collar of a stepped rivet at an operation knob.

CONSTITUTION: A resistance substrate 21 on which a resistance printed layer 22 is disposed on its one side surface, an elastic contact body 30 made of a thin elastic metal plate and having end contacts 31, 32 at positions corresponding to the layer 22 on the substrate 21, and an operation knob 34 which is rotatable at a stepped rivet 38, on which the body 30 is disposed on its one side surface and having a protrusion 40 in contact with the collar 39 of the rivet 38 on its other side surface are provided. For example, the knob 34, the substrate 21 and a clamping fitting 36 are superposed, the rivet 38 is penetrated from the side of the knob 34 through their central holes 35, 27 and 37, the end extending from the rear side of the fittings 36 is calked to be assembled as a variable resistor. Thus, a high rotary torque is obtained by the elasticity of the protrusion 40 to eliminate a problem of varying the resistance value due to an impact, a vibration, etc.