A wearable airbag device for protecting the hip of a wearer includes an airbag adapted to be worn around the pelvis and inflatable with an inflation gas. The airbag includes: an inner wall configured to face the wearer at airbag deployment; an outer wall opposite the inner wall and having a circumferential edge jointed with that of the inner wall so that the airbag has a substantially board shape when inflated; a contact portion disposed in an upper reach of a stream of inflation gas and configured to be deployed at a side of the pelvis; a protecting portion configured to be deployed in such a manner as to extend downward from the contact portion for covering an outer side of the trochanter of femur at airbag deployment; and a float-preventing means for preventing the protecting portion from floating away from the body of the wearer at airbag deployment.