To provide a member for a flexible film substrate having a highly elaborate pattern.

The member for the flexible film substrate is one formed by laminating a reinforcing plate, a peelable organic substance layer, and a flexible film having a wiring pattern on at least either surface in the given order and characterized by being formed from a composition in which the peelable organic substance layer contains an acrylic polymer, a polyfunctional monomer, a photopolymerization initiator, and a silicon monomer, the polyfunctional monomer contains at least one member selected from among a diacrylic acid ester, a dimethacrylic acid ester, a polyacrylic acid ester, and a polymethacrylic acid ester, the silicon monomer contains one or more unsaturated groups and two or more alkoxy groups in the molecule, and 35 to 100 pts.wt. polyfunctional monomer and 15 to 50 pts.wt. silicon monomer are present per 100 pts.wt. acrylic polymer.