A color cathode ray tube having an inner magnetic shield for controlling the magnetic field distribution inside of the tube. The inner shield is formed to have a pair of long side walls and a pair of short side walls provided along an inner wall of the tube's funnel. The long side wall has formed therein more than two elongated openings in each of two regions divided by a center of the long side wall. The center of the openings are offset toward the center of the long side wall.