To provide a copper alloy foil with small surface roughness, high electroconductivity, and high strength, which has adequate adhesiveness to an adhesive containing an epoxy resin without being roughened, and can be laminated to a copper-clad laminate, in a three-layer flexible substrate.

The copper alloy foil for the laminate is characterized by including particular elements, by making the thickness of the rust preventive film to be 3 nm or less from the surface, to impart the surface adequate adhesiveness to the adhesive containing the epoxy resin, by having surface roughness of 2 μm or less according to ten-points average surface roughness (Rz), and by having 180 degree peel strength of 8.0 N/cm or more when bonded to a substrate film with the adhesive containing the epoxy resin, without being roughened.