There is provided a method of producing a copper clad laminate having a copper foil and a resin bonded at high adhesive force despite the use of a thermoplastic resin having a low dielectric constant. This method includes the steps of: providing a roughened copper foil having at least one roughened surface having fine irregularities composed of acicular crystals containing cupric oxide and cuprous oxide; and bonding a sheet-shaped thermoplastic resin to the roughened surface of the roughened copper foil to provide a copper clad laminate. The roughened surface has a cupric oxide thickness of 1 to 20 nm and a cuprous oxide thickness of 15 to 70 nm, both determined by sequential electrochemical reduction analysis (SERA) at the time of bonding the thermoplastic resin.