To provide a life-saving floating body that is constituted so that an important point of the floating body emits light in order to enable a drowning person to confirm a position of the life-saving floating body when the life-saving floating body is thrown in an environment whose periphery is dark like night.

The floating body 1 used on water comprises: a power supply composed of a chargeable battery 6; a first switch which is turned on when the floating body comes off from an installation seat; a second switch which is turned on when the floating body is thrown on water and contacts with a water surface; a third switch which is turned on when peripheral light reaches a value not lower than a prescribed value; and a flashlight 4 composed of a light-emitting diode (LED) or an organic EL plate. When the floating body is thrown on the water in a status that the circumference is dark like night, the floating body comes off from a prescribed installation position or made to come off therefrom, and automatically and immediately emits light when thrown on the dark water surface and notifies its existing position by an effect that the floating body has a feature for automatically emitting light.