A variable resistor with a light emitting element includes a circuit board, a housing and a slide assembly. The circuit board extending in a longitudinal direction has a circuit arrangement surface to arrange thereon a resistive circuit and a power circuit. The housing fixed to the circuit board so as to form a slide space has a sliding slot extending in the longitudinal direction. The slide assembly further includes a slidable member, a fader set, a light emitting element, a resistive circuit brush and two light-emitting element brushes. The fader set fixed at the slidable member penetrates the sliding slot. The light emitting element in an accommodating groove of the slidable member projects a light beam toward the fader set. The resistive circuit brush electrically connects the resistive circuit. The two light-emitting element brushes electrically bridge the power circuit and the light emitting element.