A first contact target position, a second contact target position, and a characteristic pattern for specifying a position and a posture of the workpiece are set in association with each other. First and second contact target positions for measurement are specified from a workpiece image newly generated during the execution of measurement such that a driving section is controlled to bring the touch probe into contact with the side surface of the workpiece with the specified first contact target position for measurement as a reference, and the driving section is controlled to bring the touch probe into contact with the upper surface of the workpiece with the specified second contact target position for measurement as a reference. Three-dimensional coordinates of a contact point are measured based on a contact signal output when the touch probe comes into contact with the workpiece.