A semiconductor device includes a first semiconductor chip and a second semiconductor chip The first semiconductor chip includes a transmission circuit input unit, a transmission circuit unit, and a transmission unit. The second semiconductor chip includes a reception unit, a reception circuit unit, and a reception circuit output unit. The transmission unit and the reception unit can communicate with each other in a non-contact manner. A transmission circuit unit input signal having a predetermined transmission-side potential is input into the transmission circuit unit. A reception circuit unit input signal is input into the reception circuit unit via the non-contact communication between the transmission unit and the reception unit. The reception circuit unit outputs a reception circuit unit output signal having a predetermined reception-side potential. The ratio of the reception-side potential to the transmission-side potential can be changed.