It is an object of the invention to provide an injection nozzle that efficiently foams foamed aerosol content, thereby improving adhering ability onto applying part. Furthermore, facilitating the oxidization of the foamed aerosol content and improving the effectiveness of the foamed aerosol content. It is also an object of the invention to provide an aerosol injection nozzle for injecting the foamed aerosol content that the clogging is prevented even when the foamed aerosol content have a high viscosity with a simple constitution and in low cost. An aerosol injection nozzle according to the invention includes a collision wall for foamed aerosol content to be collided and interfusing with air, disposed at an injection outlets. The collision wall is disposed within a retention chamber for temporary retaining the foamed aerosol content. The aerosol injection nozzle includes an outflowing outlet for outflowing the foamed aerosol content at least at a lower side of an injection axis line between retention chamber and injection outlets.