Disclosed herein is a funnel for slim cathode ray tubes. The funnel is constructed such that the deflection angle of an electron beam is 120 degrees or more. On the assumption that, at a top of round (TOR) part located between a body and a yoke part, the thickness of each long side (x-axis) is Tx, the thickness of each short side (y-axis) is Ty, and the thickness of each diagonal part is Td, the following inequality is satisfied: Td>Tx>Ty. The TOR part has a horizontal inner curvature, a horizontal outer curvature, and a vertical outer curvature, which are convex toward the outside of the funnel, and a vertical inner curvature, which is convex toward the inside of the funnel. On the assumption that, at the body from a seal edge, at which the body is joined with a panel, to the TOR part, the thickness of each long side (x-axis) is Bx, the thickness of each short side (y-axis) is By, and the thickness of each diagonal part is Bd, the thickness ratio of the body from the seal edge to the 2/3 point of the body is set such that the following inequality is satisfied: Bx>By>Bd.