Provided is a copper foil for a printed wiring board including a roughened layer on at least one surface thereof. In the roughened layer, the average diameter D1 at the particle bottom being apart from the bottom of each particle by 10% of the particle length is 0.2 to 1.0 μm, and the ratio L1/D1 of the particle length L1 to the average diameter D1 at the particle bottom is 15 or less. In the copper foil for printed wiring board, when a copper foil for printed wiring having a roughened layer is laminated to a resin and then the copper layer is removed by etching, the sum of areas of holes accounting for the resin roughened surface having unevenness is 20% or more. The present invention involves the development of a copper foil for a semiconductor package substrate that can avoid circuit erosion without causing deterioration in other properties of the copper foil. In particular, an object of the present invention is to provide a copper foil for a printed wiring board and a method of producing the copper foil, in which the adhesion strength between the copper foil and the resin can be enhanced by improvement of the roughened layer of the copper foil.