To provide a low-voltage type wide band differential operational amplifier, with which a head room request is reduced by several tenths of volt by removing a long-tail current source.

The problem caused by the removal of the long tail current source in a conventional technology circuit is solved by using a common-mode control circuit 11. The common-mode control circuit 11 monitors a common- mode feedback current(CMFB), and when the current value exceeds the designated range near a nominal amplifier bias current, a common-mode input voltage Vin is corrected properly.