A cap assembly having a storage chamber for a secondary ingredient with an integral type working device, which comprises a cap body and a working device; said cap body including a mouth and a housing sealing part with a droping space which is formed around the mouth; said working device adapted to move vertically, including an inner extended housing which is formed with a storage chamber for containing a secondary ingredient and having at least one outlet above seal portion formed at upper portion of the working device; and when the working device containing a secondary ingredient is assembled to the mouth of the cap body, the chamber is sealed by a housing sealing part.