Knee protecting airbag device

A knee protecting airbag device comprising an airbag folded and housed in a case on the front side of the knees of a seated passenger, wherein

• the airbag includes a passenger side wall, a body side wall and tethers,
• the airbag protects the knees of a passenger when protruded rearwardly from a case and expanded and inflated upwardly, as a result of an inflating gas flowing into the airbag,
• the tethers maintain the airbag in a generally planar shape by connecting the passenger side wall to the body side wall at a time of inflation,
• the tethers are located outside of the case when the airbag is completely inflated, and
• the tethers are arranged generally horizontally in the airbag when the airbag is inflated;
• each tether is made of flexible material and is band shaped;
• each tether is sewn to the passenger side wall portion and the body side wall portion at its ends;
• and
• each tether is arranged generally horizontally along the front-rear direction.