Head protection airbag device

A head protection airbag device comprising:

• an airbag that is folded and housed on an upper edge side of a window on a vehicle inner side of a vehicle along a front-rear direction, and that is deployed and inflated downward to cover the vehicle inner side of the window when an inflation gas from an inflator flows in,
• wherein the airbag includes a window shielding inflatable portion that covers the vehicle inner side of the window when inflation is completed, and
• wherein a folded shape of the window shielding inflatable portion of the airbag includes:
• an inward roll-folded portion that is roll-folded toward the vehicle inner side such that a lower edge side of the airbag flatly deployed approaches an upper edge side;
• and
• an outward roll-folded portion that is roll-folded toward a vehicle outer side such that the inward roll-folded portion is disposed on a center side and is close to the upper edge side of the airbag.