To provide a usually wearable lifesaving jacket having the function of an airtight room capable of holding air so as to produce necessary buoyancy, prevent a person meeting with an accident from panicking and increase survival rate when he/she meets with an unexpected accident at sea, in view of the fact that many human lives are lost by accidents at sea every year and many of the lives are lost by accidents unexpected to victims, therefore in many cases the victims do not wear e.g. a life jacket.

This lifesaving jacket has airtight rooms capable of holding air and made through using a material excellent in airtightness and strength for the materials both of the front and the back of the jacket and stitching up or joining the materials. As a result of this, the jacket can produce necessary buoyancy with air existing from the beginning in the airtight rooms or by pour of expiration from a wearer at the time of drowning.