A stable reference voltage that can be supplied in a layout area smaller than prior art is provided. A current-voltage convertor includes a first current mirror circuit including a first MOS transistor, a second MOS transistor in a pair, and an output resistor; and a depletion type N-channel MOS transistor, inserted between a first voltage to be input and the first MOS transistor and the second MOS transistor, and having a gate to which an output voltage from the output resistor is fed back. When a reference current is input to the first MOS transistor, the output voltage is generated by a current corresponding to the reference current flowing into the second MOS transistor and the output resistor. In addition, a reference voltage generator including the current-voltage convertor is provided to output a reference voltage based on the output voltage of the current-voltage convertor.