Elastic member and disposable wearing article including elastic member

An elastic member having an elastic sheet stretchable structure in which an elastic sheet is interposed between a first sheet layer and a second sheet layer and the first sheet layer and the second sheet layer are bonded directly via joint holes penetrating the elastic sheet or indirectly via the elastic sheet forming a plurality of joined portions,

• wherein a region having the elastic sheet stretchable structure includes a stretchable region that contracts in a stretchable direction by contraction of the elastic sheet and is extensible in the stretchable direction, wherein the joined portions are formed in the stretchable region and arranged in a pattern in the stretchable direction and an orthogonal direction thereto, and
• wherein, in an unfolded state of the elastic sheet stretchable structure without contraction or slack, the pattern of the plurality of joined portions comprises:
• first joined portions and second joined portions, each of the second joined portions having an area smaller than an area of each of the first joined portions,
• the first joined portions are formed in staggered rows of first joined portions having a separation pitch between adjacent rows in the stretchable direction, wherein each of the first joined portions comprise an elongated shape substantially aligned along a row direction, such that a direction of elongation is either orthogonal to the stretchable direction or inclined at an inclination angle of 60 to 120 degrees with respect to thereto,
• the second joined portions are formed in rows alternating with the rows of first joined portions, and
• wherein the arrangement of the rows of first joined portions and rows of second joined portions is such that a plurality of stretchable direction lines containing no joined portions are formed in the orthogonal direction, each having a width in the orthogonal direction measured between an elongate end of a first joined portion and either an elongate end of a first joined portion in an adjacent row of first joined portions or an end of a second joined portion in an adjacent row of second joined portions being greater than 0 and 0.5 mm or less, and a plurality of oblique lines containing no joined portions are formed in the orthogonal direction each having a predetermined width in the orthogonal direction and intersecting the stretchable direction at an angle of 45 degrees or less.