A method of manufacturing a pneumatic tire has a winding step of forming a rubber ribbon winding body constructing a tread rubber by spirally winding a rubber ribbon obtained by co-extruding a first rubber and a second rubber which are different in hardness. The first rubber is mainly arranged in a first area by making a cross sectional area ratio of the first rubber greater than that of the second rubber. The second rubber is mainly arranged in a second area by making the cross sectional area ratio of the first rubber smaller than that of the second rubber. A portion in which the cross sectional area ratio of the first rubber becomes smaller by smaller is provided from the first area toward the second area. The rubber ribbon retaining a compound interface is superposed and wound to at least a part of the second area.