To provide a buoyancy bag with a built-in air pump which facilitates to send air by setting a manual air pump directly in a container of the buoyancy bag which can be inflated by taking-in air from outside.

A manual air pump 2 is installed inside a buoyancy bag container and an air inlet 5 which is opened on the outside of a buoyancy bag 1 and an air discharge port 6 which is opened in the container are provided on the pump. This structure enables to send air directly from the built-in manual air pump 2 by pumping of a pump setting surface 4 without inflating the buoyancy bag 1 by a mouth.