This invention provides a method for forming multilayer coating film, which comprises successively carrying out a step of applying an intermediate paint onto a coating object to form an intermediate coating film; a step of forming a base coating film by applying onto the intermediate coating film a water-based base coating paint; a step of forming a clear coating film by applying onto the base coating film a clear coating paint, and a step of heating the uncured intermediate coating film, base coating film and clear coating film to simultaneously cure these three coating films; wherein the intermediate paint has a complex viscosity at 40° C. (η*40) of not higher than 100 Pa·sec under the conditions of shear stress, 1.0 Pa and frequency, 0.1 Hz, and a complex viscosity at 80° C. (η*80) of at least 800 Pa·sec under the conditions of shear stress, 1.0 Pa and frequency, 0.1 Hz.