1. A position control apparatus comprising: first storage means for storing display information; a pointing device for identifying for display a portion of the display information stored in said first storage means by moving freely on a plane; detection means for detecting a vector of movement of said pointing device; calculation means for calculating a velocity of movement from the vector of movement detected by said detection means; discrimination means, responsive to at least one parameter of said vector, for discriminating whether the vector of movement of said pointing device detected by said detection means is indicative of a valid direction of movement thereof; second storage means for storing the velocity of movement calculated by said calculation means when said discrimination means discriminates that the direction of movement can be determined from said vector of movement; and control means for moving the portion identified for display at a velocity corresponding to the velocity stored in said second storage means even when the movement of said pointing device is stopped.