A variable resistor according to the present invention includes a substrate, a resistive element disposed on a first surface of the substrate, oil that coats an upper surface of the resistive element, and a slide member that slides on the upper surface of the resistive element coated with the oil, wherein an output of the variable registor changes as a position at which the slide member makes contact with the resistive element changes. The variable resistor further includes an oil repellent part that surrounds at least a part of the resistive element in plan view viewed from above the first surface of the substrate, the oil repellant part having surface free energy smaller than that of the resistive element, whereby oil can be stably held on a resistive element surface without forming irregularities on the resistive element surface.