To reduce the manufacturing variance of a voltage generation circuit of the output of a reference voltage, by using only a resistance and an enhancement type MOS transistors TR being a surface-channel type to specify the constitution of the voltage generation circuit.

This circuit is composed of a resistance 11, the MOS TR 13, 15, 17 and 19 which are connected together. The 1st and 2nd p-channel TR 13 and 19 are equal to the enhancement type MOS TRs which have the p-type polycrystal silicone films as the gate electrodes, and the 1st and 2nd TR 15 and 17 are equal to the enhancement type MOS TR which have the n-type polycrystal silicone films as the gate electrodes. Furthermore, the same threshold voltage is secured between both TR 13 and 19 and also between both TR 15 and 17 respectively. Then the ratio set between the channel width and length of the TR 13 is set larger than that of the TR 15, and the value of the resistance 11 is adjusted to increase the reference voltage output by about 1.5 times as large as the threshold voltage of the TR 15.