When a low level voltage is inputted to an input terminal IN, a transistor EF1 enters a blocked state, a first switch circuit SW1 enters a conduction state, and a second switch circuit SW2 enters the blocked state. Accordingly, a boosted voltage outputted from a voltage booster circuit CP is applied to a load R. When a high level voltage is inputted to the input terminal IN, the transistor EF1 enters the conduction state, the first switch circuit SW1 enters the blocked state, and the second switch circuit SW2 enters the conduction state. Accordingly, a voltage equivalent to that at the external power supply terminal VDD is applied to the load R. Therefore, although a current constantly flows through the transistor EF1 when the boosted voltage is not required, such situation does not affect a current supplied from the voltage booster circuit CP.