To provide an air bag for a front passenger seat which enables an occupant side wall part to be vertically widely deployed in an early stage of expansion.

An almost cylindrical straightening fabric 36 with both opened ends in front and rear directions is arranged in an air bag main body 15 to cover an upper side of a gas inflow port 21 and straighten expansion gas flowed from the gas inflow port 21 in the air bag 14 for the front passenger seat. Preliminarily folded shape is a shape in which a peripheral wall part 18 is folded and flatly superposed from an upper side to a lower side of a peripheral wall part 18 while an almost all area of the occupant side wall part 16 being flatly deployed. A part in the vicinity of a connecting position with an upper edge of the occupant side wall part 16 in a peripheral wall part 18 is folded in with a valley folding line CH along left and right directions. The folding line CH is arranged rearwardly of a rear edge 20b of the gas inflow port 21. The straightening fabric 36 is arranged to locate a rear end 36a near the folding line CH and forwardly thereof at completion of preliminary folding.