To release air and remove a button without holding the button by hand in disposing an aerosol container.

This cap 40 covers an aerosol container 10 covering a button 30 which jets out a content with gas by pressing the button 30. The cap 40 is provided with a button lock-on part 50 for keeping the button 30 depressed for releasing the gas thoroughly and a button removing part 60 for dismounting the button 30 from a stem 21 in removing the cap 40.