To provide an etching gaseous mixture for transition metallic films and an etching method using this mixture.

This gaseous mixture consists of a first gas which is any selected from gaseous halogen, gaseous halide, gaseous halogen mixture, gaseous halide mixture and a mixture composed of the gaseous halogen and the gaseous halide and a second gas which is any selected from gaseous carbon oxides, gaseous hydrocarbons, gaseous nitrogen oxides and gaseous nitrogen. As a result, the etching gaseous mixture for the transition metallic films forms metal halide having high volatility by reacting with the transition metallic films and is, therefore, capable of forming fine patterns while maintaining high selectivity.