The airbag device for front passenger's seat of the present invention includes an airbag protruding and deploying from an opening for protrusion in instrument panel in front of front passenger's seat when activated. The airbag includes a bag-shaped airbag body constituting outer wall of the airbag, and a flow regulating cloth disposed inside the airbag body. The flow regulating cloth inflates firstly upon inflow of inflation gas, and redirects the gas before supplying the same to the airbag body for promoting deployment of the airbag body. The flow regulating cloth includes a circumferential wall provided with left and right gas outlet ports for emitting gas outward in left and right directions. When the airbag is inflated, parts of the circumferential wall of the left and right outlet ports project from the opening in instrument panel in left-right direction, such that the parts deploy above top face of the instrument panel in a periphery of the opening. The airbag device of the present invention stably suppresses partial protrusion of the airbag toward front passenger's seat in the initial stage of inflation.