Two sheets (2a, 2b) facing each other and a plurality of elastic members extending along this direction so as to be able to expand and contract in the expansion / contraction direction of the composite expansion / contraction member (1) between the sheets (2a, 2b) (10), each sheet (2a, 2b) is joined to each other by a plurality of joints (4), and each joint (4) is continuously extended along a line intersecting with the expansion / contraction direction, respectively. The elastic members (10) are configured to intersect with the plurality of elastic members (10), and the elastic members (10) are bonded to the sheets (2a, 2b) at the intersections with the bonding portions (4), respectively.互いに対向する２枚のシート（２ａ，２ｂ）と、各シート（２ａ，２ｂ）の間で複合伸縮部材（１）の伸縮方向に伸縮可能となるようにこの方向に沿って延びる複数の弾性部材（１０）とを設け、各シート（２ａ，２ｂ）を複数の接合部（４）で互いに接合し、各接合部（４）をそれぞれ前記伸縮方向と交差する線に沿って連続的に延びて複数の弾性部材（１０）と交差するように構成するとともに、各弾性部材（１０）を、各接合部（４）との交差点においてそれぞれ各シート（２ａ，２ｂ）に接合する。
