To provide a water-based coating composition for outer surface of can capable of forming a coated film excellent in abrasion resistance, scratch resistance and slip characteristics, scarcely causing removal of a wax component, etc., from the surface and using wax co-dispersions.

In the water-based coating composition, (A) a wax co-dispersion obtained by dispersing (a) a wax having >70°C and ≤110°C melting point and 10-50 acid value and (b) a wax having 10-70°C melting point into an organic solvent and (B) a wax co-dispersion obtained by dispersing the wax (a) and (c) a tetrafluoroethylene-based resin into an organic solvent are contained so as to satisfy the formulas [(b)+(c)]/(a)=80/20 to 60/40 and (b)/(c)=15/85 to 50/50 and (C) a coating resin is further contained.