A stroke operation calibration control device for a hydraulic cylinder includes: movable portions; hydraulic cylinders; a stroke sensor measuring a stroke length of the hydraulic cylinder; a reset sensor measuring a reset reference point at which a measurement value of the stroke length obtained by the stroke sensor is reset; a stroke end detection process unit detecting a stroke end position of the hydraulic cylinder; a calibration process unit calibrating the measurement value of the stroke length upon the detection of the reset reference point and/or the stroke end position; a malfunction detection unit outputting an error when the stroke length is in the predetermined measurement range; and a control unit prohibiting the reset until the stroke length has passed the reset reference point at power input time.