A voltage detection circuit of the present invention includes an NMOS transistor diode-connected, a gate and a drain thereof being supplied with a power supply voltage, a resistor connected between a source of the NMOS transistor and a ground potential, and a source voltage detection circuit receiving a voltage of the source, wherein an NMOS type transistor is employed as the NMOS transistor, a channel width and a channel length of the NMOS type transistor being set in such a manner that an operating point on a VG-ID curve of the NMOS type transistor may come to a certain point, at the certain point, a drain current of the NMOS type transistor being constant even if the temperature fluctuates.