An airbag apparatus according to the present exemplary embodiment includes: an airbag housing which accommodates an airbag; and an airbag cover which is coupled to the airbag housing while covering the airbag accommodated in the airbag housing, and has a tear line that is torn by expansive force of the airbag, in which the airbag cover is opened while being rotated about a portion between both ends of the tear line as a rotation center when the tear line is torn, and first notch portions, which are cut out in a direction in which the first notch portions cross both ends of the tear line, are formed at both ends of the tear line, respectively, thereby allowing the airbag to be deployed in accordance with design intention.