To provide a method for producing a coated paper for rotary offset printing, excellent in smoothness, gloss and stiffness and having excellent running stability on a rotary offset press by using a base paper prepared by forming a sheet of the base paper with a paper machine having a gap type twin-wire former.

A sheet of base paper is produced by dehydration at the ratio of dehydration amount (top wire side/bottom wire side) onto both wire sides until the raw material solid concentration attains 2.5 wt.% in a twin-wire former part within the range of ≥0.85 and ≤1.15 with a wet press device containing one or more presses of a wide nip, and a coating layer is then formed on the base paper. The resultant coated base paper is subsequently threaded through a hot soft calender to carry out the smoothing and finishing treatments in the production of a coated paper for rotary offset printing by coating and drying the formed sheet of the base paper prepared by using a gap type twin- wire former with a water-soluble coating composition consisting essentially of a pigment and an adhesive and finishing the dried coated base paper. The wet press device of the wide nip is a shoe pressing type wet press device.