A coating method for forming a laminated coating film including a lower layer formed on a base material and an upper layer formed on the lower layer, the coating method comprising: a preparation step of preparing a thermosetting coating material as a lower layer-coating material for forming the lower layer and preparing a thermosetting coating material as an upper layer-coating material for forming the upper layer; a formation step of forming an uncured laminated coating film by applying the lower layer-coating material and the upper layer-coating material on the base material using a wet-on-wet technique; and a baking step of simultaneously curing the lower layer-coating material and the upper layer-coating material by subjecting the uncured laminated coating film to a baking treatment, wherein in the preparation step, the lower layer-coating material and the upper layer-coating material are selected so that an absolute value of a difference in shrinkage ratio between the lower layer-coating material and the upper layer-coating material is 1.0% or smaller at a late stage of the baking in the baking step, said shrinkage ratio being calculated on the basis of the formula: ω ′ = 100 Y − Z / Z − X (in the formula, ω' represents the shrinkage ratio (%) mainly attributable to volatile products, X represents the weight (g) of the sample base material, Y represents the weight (g) of the sample base material and the coating film after a preliminary drying, and Z represents the weight (g) of the sample base material and the coating film after the curing by heating at 140°C for 30 minutes), and said late stage of the baking being a period after the preliminary drying state in which water has been removed by drying the coating film at 80°C for 3 hours and then in a vacuum at 60°C for 96 hours, up to a completion state in which the coating film has been baked at 140°C for 30 minutes. a preparation step of preparing a thermosetting coating material as a lower layer-coating material for forming the lower layer and preparing a thermosetting coating material as an upper layer-coating material for forming the upper layer; a formation step of forming an uncured laminated coating film by applying the lower layer-coating material and the upper layer-coating material on the base material using a wet-on-wet technique; and a baking step of simultaneously curing the lower layer-coating material and the upper layer-coating material by subjecting the uncured laminated coating film to a baking treatment, wherein in the preparation step, the lower layer-coating material and the upper layer-coating material are selected so that an absolute value of a difference in shrinkage ratio between the lower layer-coating material and the upper layer-coating material is 1.0% or smaller at a late stage of the baking in the baking step, said shrinkage ratio being calculated on the basis of the formula: ω ′ = 100 Y − Z / Z − X (in the formula, ω' represents the shrinkage ratio (%) mainly attributable to volatile products, X represents the weight (g) of the sample base material, Y represents the weight (g) of the sample base material and the coating film after a preliminary drying, and Z represents the weight (g) of the sample base material and the coating film after the curing by heating at 140°C for 30 minutes), and said late stage of the baking being a period after the preliminary drying state in which water has been removed by drying the coating film at 80°C for 3 hours and then in a vacuum at 60°C for 96 hours, up to a completion state in which the coating film has been baked at 140°C for 30 minutes.