Provided herein is a carrier-attached copper foil having desirable laser drillability through an ultrathin copper layer, preferred for fabrication of a high-density integrated circuit substrate. The carrier-attached copper foil includes an interlayer and an ultrathin copper layer that are provided in this order on one or both surfaces of a carrier. The surface roughness Sz and the surface roughness Sa on the interlayer side of the ultrathin copper layer satisfy Sz≤3.6 μm, and Sz/Sa≤14.00 as measured with a laser microscope in case of detaching the carrier from the carrier-attached copper foil according to JIS C 6471 after the carrier-attached copper foil is laminated to an insulating substrate from the ultrathin copper layer side under a pressure of 20 kgf/cm2 and heated at 220° C. for 2 hours. GMD, which is a 60-degree glossiness of the ultrathin copper layer surface on the interlayer side in MD direction, satisfies GMD≤150 in case of detaching the carrier from the carrier-attached copper foil according to JIS C 6471 after the carrier-attached copper foil is laminated using the same procedure.