A plurality of belt layers 7 are superimposed in a radial direction. The belt layers 7 include a plurality of steel cords 10 arranged in parallel in a row and rubber 11. The steel cords 10 have a 1×4 structure in which four filaments 20 are twisted, and when a center-to-center distance between the steel cords 10 in at least two of the belt layers 7 adjacent in the radial direction is T, and an average diameter of virtual circumscribed circles of the steel cords 10 having the 1×4 structure is D, 1.25≤T/D≤2.25.