To provide an airbag, quickly developed in an area for the airbag to be developed without using a device with high output power to serve as an inflator and a protection apparatus for a pedestrian or the like including the airbag.

When a contact of a pedestrian or the like is detected or predicted, the inflator 14 is activated and the airbag 10 is developed. The gas from the inflator 14 is supplied into a first bag 11 first, and the first bag 11 is thereby expanded at a high internal pressure and is developed along a cowl top 2 and an A pillar 6. Thereafter, the gas flows into the second bag 12 from the first bag 11 passing through an opening 13 that allows an inner part of the first bag 11 to communicate with that of the second bag 12, and develops the second bag 12. Since the first bag 11 is expanded and developed first, the first bag 11 can be sufficiently and promptly developed in an area for the first bag 11 to be developed without using a device with high output power to serve as the inflator 14.