To provide a valve positioner capable of dealing with the abnormality of a microprocessor even in various control valves having respectively different parameters.

The valve positioner having a microprocessor 1 for sending a deviation between an input signal and an output from a position detector 7 as a drive signal corresponding to the input signal, an actualtor 5 for outputting a signal corresponding to an output from the microprocessor 1 to a control valve 6 and the position detector 7 for detecting the driven state of the control valve and converting the detected state into an electric signal is also provided with an abnormal time set point storing means 10 for storing a value capable of driving the control valve 6 so as not to generate an accident in a process as an output from the actuator 5, an operation means 11 for calculating the set value stored in the means 10 and the deviation between the output of the detector 7 and the input signal, a means 12 for switching an output signal from the means 11 to an output signal from the microprocessor 1 when abnormality occurs in the microprocessor 1 and supplying the switched signal to the actuator 5 and a means for setting up a control parameter for the valve 6 in the means 11.