A color cathode-ray tube includes a panel portion, a neck portion, a funnel portion connecting the panel and neck portions, a fluorescent layer formed on an inner surface of a face plate of the panel portion, a shadow mask disposed opposite to the fluorescent layer, an electron gun housed in the neck portion, and an internal magnetic shield disposed in the funnel portion. The internal magnetic shield is formed in a substantially quadrangular pyramid-shape having a substantially rectangular first opening with a smaller diagonal at one end adjacent to the electron gun and a substantially rectangular second opening with a larger diagonal dimension than the smaller diagonal dimension at the other end adjacent to the shadow mask. The internal magnetic shield has a long side wall including a long side of the first opening and a size adjustment side wall for the long side connecting to the long side wall at one end adjacent to the shadow mask which lie in substantially a single plane, and has a short side wall including a short side of the first opening and a size adjusting side wall for the short side connecting to the short side wall at one end adjacent to the shadow mask.