To permit the pin seam to be easily inserted into the weft loop at the seam part by keeping the virtual plane of the weft loop always rectangular to the warp and suppressing the occurrence of latent force to incline the virtual plane to the warp.

When the weaving operation is carried out by using a couple of one weft and one warp constituting one loop, the first warp passes through between the wefts from the front face of the coupled weft to the back face of the adjacent weft, while the second warp passes through between the wefts from back face of the coupled weft to the front face of the adjacent weft and these yarn motions are repeated to give a yarn texture in which the warp appears on the front face and the back face alternately. Further, bag-like base cloth that has a loop in one ear and can be converted from the endlessly circular state to the extended state is constituted with textures by using 3 warps except the selvages at the edges of the base cloth. Then, the butts are entangled to one face or both faces of the base cloth by needling.