To enable position or distance of sensing target making approach, etc. to the range of sensing area to be detected securely with simple configuration at low cost and improve latitude of designing, position detector includes capacitance sensor unit and detecting circuit unit. Capacitance sensor unit includes first and second sensing electrodes and dielectric material therebetween. Dielectric material has range L of sensing area defined on its sensing surface. Detecting circuit unit includes selector switches SWA and SWB, capacitance sensing circuits, A/D converters, and arithmetic processing circuit. Arithmetic processing circuit judges and detects the position of sensing target in range L of sensing area based on detected values of capacitances C1 and C2 sensed by first and second sensing electrodes under switching control on selector switches SWA and SWB.