The severely handicapped often uses breath pressure for an input method to control various instruments such as TV, motorized bed, curtain, air conditioner in everyday life. Most of the input devices are ON/OFF (digital) type for the control of equipments. Considering the application of electrically powered wheelchair, the ON/OFF type interface is not desirable. Because the control of powered wheelchair needs preciseness and quickness for safe operation. A new input device using breath pressure is proposed for such purposes. The paper examines basic performances of human breath pressure control as an analog input device. Then possibility of two-dimensional input device by the breath pressure is discussed for the control of powered wheelchair. Basic experiments to study performance of the two-dimensional analog input device by breath pressure for an operation of the powered wheelchair are shown.