The charge/discharge phenomenon of capacitance between terminals in a power MOSFET affects on its switching behavior of the device. The input capacitance is composed of the gate-source capacitance C_GS and the gate-drain capacitance C_GD, which vary with gate voltage V_GS. This paper characterizes the relationship between the input capacitance of a SiC MOSFET and the gate voltage with considering the internal device structure. The results give us a clue to understand the switching dynamics of the power MOSFET.