A analog quantity control device is prepared as setting the second single step timer on said control unit, utilizing the coding unit to count up number of syntropic jump off edge at data signal inputted by control/data single tube pin in preset time being confirmed by the second single step timer and using said coding unit to latch said number of syntropic jump off edge, carrying out coding on itaccording to mode of corresponding each preset number of syntropic jump off edges to one code and inputting coded result to decoding unit, being used to decode said result to be analog quantity to beoutputted according to linear decoding mode.