A semiconductor device can output a reference voltage for an arbitrary potential and can detect the voltage of each cell in a battery including multiple cells very precisely. The device includes a depletion-type MOSFET 21 and an enhancement type MOSFET 22, and has a floating structure that isolates depletion-type MOSFET 21 and enhancement type MOSFET 22 from a ground terminal. The depletion-type MOSFET 21 and enhancement type MOSFET 22 are connected in series to each other, wherein the depletion-type MOSFET 21 is connected to high-potential-side terminal and the enhancement type MOSFET 22 is connected to low-potential-side terminal. The semiconductor device having the configuration described above is disposed in a voltage detecting circuit section in a control IC for a battery including multiple cells.