Seat pad manufacturing method

A seat pad manufacturing method comprising:

• a sheet disposition step of disposing a sheet member inside a foaming mold for shaping a seat pad;
• a foaming step of injecting a foaming resin material into the foaming mold and foaming a resin foamed body through mold clamping after the sheet disposition step;
• and
• a demolding step of demolding the resin foamed body in a state in which the sheet member is buried in the resin foamed body, wherein
• the foaming mold includes a lower mold piece having a lower-mold-piece shaping surface for shaping a surface of the seat pad on a seated person side, and an upper mold piece having an upper-mold-piece shaping surface for shaping a back surface of the seat pad, and
• when a direction orthogonal to a right-left direction and a thickness direction of the seat pad is referred to as an extending direction of the seat pad,
• in the sheet disposition step, both end parts of the sheet member in the right-left direction and both end parts of the sheet member in the extending direction are each temporarily fastened to the lower-mold-piece shaping surface or the upper-mold-piece shaping surface through one or a plurality of fasteners, and
• in the foaming step, the foaming resin material is injected into a space between the lower-mold-piece shaping surface and the sheet member, and at least a central part of the sheet member deforms into a shape curved in a convex shape on the upper-mold-piece shaping surface side in each of the right-left direction and the extending direction as the sheet member is pressed upward to the upper-mold-piece shaping surface side through expansion of the foaming resin material.