A far-side airbag apparatus configured to be applied to a vehicle, the vehicle including a plurality of vehicle seats arranged in parallel in a width direction of the vehicle seats, two side portions of the vehicle in the width direction being constituted by a pair of side wall portions, one of the two side wall portions being set to a specific side wall portion, an airbag being unfolded and inflated by inflation gas between adjacent vehicle seats when it is detected that an impact is applied to the specific side wall portion from outside or when it is predicted that an impact will be applied to the specific side wall portion, wherein a bag body constituting an outer shell part of the airbag includes a lower inflation portion that is unfolded and inflated at least on a lateral side of a chest among parts below a neck (PN) of an occupant (P1) seated in one of the adjacent vehicle seats , and an upper inflation portion that is unfolded and inflated on a lateral side of a part above the chest (PT) of the occupant (P1) in a state in which the upper inflation portion is inclined to approach the occupant (P1) toward an upper side, characterized in that the lower inflation portion is formed by joining a surface lower cloth portion on a side close to the occupant (P1) and a back lower cloth portion on a side far from the occupant at a peripheral edge portion different from an upper peripheral edge portion, the upper inflation portion is formed by joining a surface upper cloth portion on a side close to the occupant (P1) and a back upper cloth portion on a side far from the occupant (P1) at a peripheral edge portion different from a lower peripheral edge portion, and the surface lower cloth portion , the back lower cloth portion , and the surface upper cloth portion are integrally formed of a large cloth sheet , the back upper cloth portion is formed of a small cloth sheet smaller than the large cloth sheet , and a lower peripheral edge portion of the back upper cloth portion is joined to an upper peripheral edge portion of the back lower cloth portion . wherein a bag body constituting an outer shell part of the airbag includes a lower inflation portion that is unfolded and inflated at least on a lateral side of a chest among parts below a neck (PN) of an occupant (P1) seated in one of the adjacent vehicle seats , and an upper inflation portion that is unfolded and inflated on a lateral side of a part above the chest (PT) of the occupant (P1) in a state in which the upper inflation portion is inclined to approach the occupant (P1) toward an upper side, characterized in that the lower inflation portion is formed by joining a surface lower cloth portion on a side close to the occupant (P1) and a back lower cloth portion on a side far from the occupant at a peripheral edge portion different from an upper peripheral edge portion, the upper inflation portion is formed by joining a surface upper cloth portion on a side close to the occupant (P1) and a back upper cloth portion on a side far from the occupant (P1) at a peripheral edge portion different from a lower peripheral edge portion, and the surface lower cloth portion , the back lower cloth portion , and the surface upper cloth portion are integrally formed of a large cloth sheet , the back upper cloth portion is formed of a small cloth sheet smaller than the large cloth sheet , and a lower peripheral edge portion of the back upper cloth portion is joined to an upper peripheral edge portion of the back lower cloth portion . <EOS>