To produce an ultra-thin copper foil with a carrier foil that microscopic crystal grains can be deposited without being affected by the surface roughness of a carrier foil, etching can be performed until an ultra-fine width such that line/space is 15 mum or less, and the microscopic line and a wiring board have large peel strength even after line of 15 mum is etched. An ultra-thin copper foil wherein a carrier foil, a peeling layer, an ultra-thin copper foil are laminated in this order, the ultra-thin copper foil (before roughening treatment is performed) is an electrolytic copper foil that surface roughness of 2.5 mum as ten point height of roughness profile, and the minimum distance between peaks of salients of a based material is 5 mum or more. Moreover, the surface of the ultra-thin copper foil is performed roughening treatment.