Automobile water-based paint

An automobile water-based paint which comprises hydroxyl-containing resin (A), viscosity-regulating agent (B) and hydrophobic solvent (C), characterized in that the viscosity-regulating agent (B) is a copolymer obtained by copolymerizing a mixture of polymerizable unsaturated monomers comprising 1-50 mass % of (meth)acrylic acid (salt) (b-1), 5-60 mass % of polymerizable unsaturated monomer (b-2) represented by the following general formula (1):

• in which
• R1 stands for hydrogen or methyl,
• R2 and R3 stand for hydrogen, methyl or ethyl,
• R4 stands for C8-24 hydrocarbon group, and
• n is an integer of 3-60,
• 5-60 mass % of alkyl (meth)acrylate (b-3) of which alkyl moiety has 1-4 carbons, and 0.05-5 mass % of polymerizable unsaturated monomer (b-4) having at least two polymerizable unsaturated groups per molecule, based on the combined mass of the polymerizable unsaturated monomers (b-1)-(b-4).