A composite sheet having an elastic layer and an inelastic layer and high breathability and a method for manufacturing such improved composite sheet. The composite sheet includes an elastic layer and an inelastic layer joined and laminated through a plurality of joints. The elastic layer is formed with first depressions overlapping the joints and extending in a transverse direction and first protrusions. Interior space if the first protrusions is filled with constituent fibers of the elastic layer. The inelastic layer is formed with second depressions overlapping the joints and extending in a longitudinal direction and second protrusions. Along the second depressions, the elastic layer and the inelastic layer come in contact with each other at the joints and, along the second protrusions, the inelastic layer is spaced from the elastic layer to define clearance gaps in these layers.