The purpose of this invention is, in producing a pleated composite extensible member, to provide a composite extensible member which is flexible, has an agreeable texture, and has a good skin feel, and to firmly fix a first sheet-form nonwoven fabric to a string-form elastic member in a stretched state and a second sheet-form nonwoven fabric. In the transferring step, the first sheet-form nonwoven fabric and the string-form elastic member (rubber thread, etc.) in a stretched state are positioned on the protruding surface side of a pattern roller, and at the position on the pattern roller where the protruding surface is present, hot-melt adhesive is applied to the stretched string-form elastic member and the first sheet-form nonwoven fabric, intermittently in the direction of travel of the stretched string-form elastic member, and in the subsequent nip-roller step, the stretched string-form elastic member and the first sheet-form nonwoven fabric to which hot-melt adhesive was applied in the previous step are firmly affixed to the second sheet-form nonwoven fabric, and a piece of the first sheet-form nonwoven fabric and a piece of the second sheet-form nonwoven fabric are adhered together with hot-melt adhesive applied intermittently to the string-form elastic member at a position corresponding to the position on the pattern roller at which the protruding surface is present. In this extensible composite sheet, the two layers of breather (pleats) <；gather>； are made to face one another, with the valleys of the upward-facing breather (pleats) <；gather>； of the upper nonwoven fabric sheet and the valleys of the downward-facing breather (pleats) <；gather>； of the lower nonwoven fabric sheet fixed together by adhesion in two-dimensional positions, with a plurality of extensible members (rubber thread) between the two nonwoven fabric sheets, and the fixing area provided by two-dimensional positions is a flat shape made by the protruding surface of the pattern ro
