A polycarbonate polyol having a main chain of the formula: ##STR1## wherein R is an aliphatic or alicyclic hydrocarbon group having 4 to 10 carbon atoms, and n is a number of 2.00 to 20.00, and having an aliphatic OH group at the terminal; an aromatic polycarbonate polyurethane resin prepared from the polycarbonate polyol as set forth above and a polyisocyanate compound having two or more isocyanate groups in the molecule and optionally other components, particularly a chain extender having a polar group; a coating agent comprising the polycarbonate polyol and/or aromatic polycarbonate polyurethane resin as set forth above and optionally a polyisocyanate compound as set forth above and a solvent; a cast film comprising a coating film formed from the polycarbonate polyol and/or aromatic polycarbonate polyurethane resin as set forth above and a base film; and a magnetic recording medium comprising a magnetic layer formed from the aromatic polycarbonate polyurethane resin as set forth above and optionally the polyisocyanate compound as set forth above, and a base film.