A calibration device for gauges for the measurement of the geometrical characteristics of cylinders, such as the diameter, profile, rotundity and eccentricity errors, wherein such gauges include a pair of movable opposing arms equipped with feelers or sensors at their free ends, includes a pair of abutments reciprocally approachable and/or withdrawable by means of motors until a sample measure is obtained, as desired, within the measuring range of the gauge, on which the calibration device is assembled, revealed by means of measuring means cooperating with the abutments, such that consequently the feelers or sensors are respectively abutted or approached to the abutments to reveal the sample measure.