In this paper, the equations which can be used to calculate the minimum series stabilizing resistance and /or the minimum parallel stabilizing conductance using the S parameters of an active device has been derived. The equation derived can be used to design a stabilizing circuit of minimum loss of a maximum available gain of a device when the circuit is adopted. For the case of KGF1254B which can be used at 1.9GHz, the circuit proposed in this paper reduce the maximum available gain by 1㏈, while conventional simple resistor circuit reduce it by 5.2㏈.