PURPOSE: To transmit no abnormal current signal to a load side when the power source of the two-wire type transmitter which is supplied with electric power from the load side through two transmission lines to convert a physical quantity to be measured into an electric signal, processes the electric signal by a microprocessor, and sends the current signal to the load side through the transmission lines is turned on.

CONSTITUTION: The two-wire type transmitter is equipped with a 1st power circuit PC1 which rises in voltage first when supplied with the electric power and supplies a constant circuit voltage, a 2nd power circuit PC-2 which has the voltage settled after the circuit voltage and supplies the processor source voltage, and a control circuit CNT which is supplied with the circuit voltage and outputs a reset signal for resetting the microprocessor at specific time after the processor source voltage settles and a switching signal after the reset signal, a fixed voltage source which sets the current signal supplied to the load to a specific fixed current, and a switching means which performs switching from the fixed current source to the output of the microprocessor with the switching signal.