For providing a hysteresis characteristic setting device configured by components smaller in number than those of a logic circuit or a comparator circuit for setting a hysteresis characteristic, the device comprises a resistor voltage dividing circuit including two resistors (R1,R2); and a microcomputer (30) including first and second ports (I1,I2) and serving as input ports. When an output signal from a low-pass filter circuit (10) is supplied to the device; the voltage of the signal is divided by the two resistors of the resistor voltage dividing circuit and then given to the second port. The microcomputer performs a process according to a combination of levels Hi and Lo detected in the ports, to set a hysteresis characteristic in which an input voltage level corresponding to a threshold voltage level of the first port is a lower limit, and that corresponding to a threshold voltage level of the second port is an upper limit.
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