An airbag deployment assistance member capable of suppressing a variation in rotation amount during airbag deployment and increasing stability of an airbag deployment direction. The airbag deployment assistance member includes an attachment portion attached to a body of a vehicle (V), a holding portion that holds a curtain airbag in a folded state on the inner side, and a hinge portion that connects one end of the attachment portion and a first portion of the holding portion. During deployment of the curtain airbag, the entire holding portion rotates about the hinge portion by the deployment force of the curtain airbag until an outer portion of the first portion makes contact with portions of the attachment portion close to an interior garnish. After the contact, a second portion of the holding portion is allowed to be deformed so as to be open in relation to the first portion.