A reference voltage generator circuit comprises a first current path and a second current path. The first current path is formed between an input terminal supplied with a first reference voltage and an output terminal and including a first diode and a first resistor serially connected from the input terminal. The second current path is formed between the input terminal and the output terminal and including a second diode, a second resistor and a third resistor serially connected from the input terminal. A comparator is supplied with a voltage on a node between the first diode and the first resistor and a voltage on a node between the second resistor and the third resistor for comparative amplification. A transistor is connected between the output terminal and a second reference voltage and having a control terminal to receive an output from the first comparator.