A method for separating and removing a rigid core when building a tire. When the rigid core body is to be separated and removed from the inside of the tire, the method includes removing a core holding mechanism and upper and lower support plates; transferring the tire to a support table; raising a second core separation/removal mechanism; horizontally pulling a first type of segment groups until separated from the inner surface of the tire; lowering the first type of the segment groups below the support table; lowering a first core separation/removal mechanism to the center of the height position of the rigid core body; horizontally pulling the second type of the segment groups until they are separated from the inner surface of the tire; transferring a second type of the segment groups with a second core separation/removal mechanism, and conveying the tire to the subsequent process.