An occupant restraining device for a vehicle that can regulate a position of a seat belt, without occupying vehicle cabin space. An air belt device includes a retractor that is arranged to the rear, in a vehicle front-rear direction, with respect to a seat back, a seat belt that is pulled out from the retractor when applied to an occupant and that includes a shoulder belt portion for restraining an upper body of the occupant, and a belt insertion portion that is formed by indenting a portion, in a seat width direction, of an upper end of the seat back, and into which an upper side portion of the shoulder belt portion of the seat belt is made to enter.