To provide a water-based coating composition exhibiting a good appearance even if the composition has high solid ratio to 40-60% when coated and to provide a method for forming a coated film and a coated product comprising the water-based coating composition as an intermediate coated film.

This water-based coating composition comprises a polyester resin, acrylic resin and melamine resin as vehicles. The polyester resin has 500-5,000 number-average molecular weight [Mn (P)] and the acrylic resin has 1,000-10,000 number-average molecular weight [Mn (A)] in the composition. Furthermore, Mn (P) and Mn (A) have the relationship of Mn (A)=(1.1 to 10)×Mn (P).