A passenger seat airbag device comprising: an airbag door provided at an instrument panel; an airbag that is provided in a folded state at a rear side of the airbag door, pushes and opens the airbag door upon receiving a supply of gas, and is inflated and deployed at a front surface side of the instrument panel; a protruding portion that is engaged with an engagement hole formed in the airbag door, in a state in which a distal end portion of the protruding portion protrudes from a rear surface of the airbag door; and a decorative panel including a door decorative portion that is formed integrally with the protruding portion and is attached to the front surface of the airbag door by engaging the protruding portion with the engagement hole; and a protective plate that includes a protective portion covering the distal end portion of the protruding portion from the airbag side and is provided at the rear surface of the airbag door characterised in that the airbag door is connected to the instrument panel by a pair of planned vertical rupture portions (50,52) arranged side by side in the width direction of a vehicle and extending in the up-down direction of the vehicle; and the decorative panel includes panel decorative portions (80,82) that are disposed opposite the door decorative portion, with one of the pair of planned vertical rupture portions (50,52) being interposed between each of the panel decorative portions wand the door decorative portion, and attached to the front surface of the instrument panel, and connected to the door decorative portion by thin portions (96,98), each of the thin portions extending in the vertical direction of the vehicle along one planned vertical rupture portion (50,52). an airbag door provided at an instrument panel; an airbag that is provided in a folded state at a rear side of the airbag door, pushes and opens the airbag door upon receiving a supply of gas, and is inflated and deployed at a front surface side of the instrument panel; a protruding portion that is engaged with an engagement hole formed in the airbag door, in a state in which a distal end portion of the protruding portion protrudes from a rear surface of the airbag door; and a decorative panel including a door decorative portion that is formed integrally with the protruding portion and is attached to the front surface of the airbag door by engaging the protruding portion with the engagement hole; and a protective plate that includes a protective portion covering the distal end portion of the protruding portion from the airbag side and is provided at the rear surface of the airbag door characterised in that the airbag door is connected to the instrument panel by a pair of planned vertical rupture portions (50,52) arranged side by side in the width direction of a vehicle and extending in the up-down direction of the vehicle; and the decorative panel includes panel decorative portions (80,82) that are disposed opposite the door decorative portion, with one of the pair of planned vertical rupture portions (50,52) being interposed between each of the panel decorative portions wand the door decorative portion, and attached to the front surface of the instrument panel, and connected to the door decorative portion by thin portions (96,98), each of the thin portions extending in the vertical direction of the vehicle along one planned vertical rupture portion (50,52).