Disclosed is a 3-dimensional model-processing apparatus capable of processing a 3-dimensional model appearing on a display unit including a sensor for generating information on the position and the posture, which can be controlled by the user arbitrarily, and control means for carrying out a grasp-state-setting process of taking a relation between the sensor-generated information on the position and the posture of the sensor and information on the position and the posture of the 3-dimensional model appearing on the display unit as a constraint relation on the basis of a relation between the 3-dimensional position of the 3-dimensional model appearing on the display unit and the 3-dimensional position of a tool appearing on the display unit for the sensor or on the basis of a relation between the 3-dimensional posture of the 3-dimensional model appearing on the display unit and the 3-dimensional posture of the tool appearing on the display unit for the sensor.