A knee protection airbag apparatus of this invention has an airbag having a construction in which folded and accommodated below the area in front of the knees of a passenger who is seated, and inflates upward toward the rear of the vehicle so as to be capable of protecting the knees of the passenger, when an inflating gas is inserted. The airbag includes a knee protection inflation portion which is disposed on the upper side of the airbag after completion of inflation and which is capable of protecting both knees of the passenger, and a shin facing portion disposed below the knee protection inflation portion after completion of inflation, in an area extending substantially vertically so as to be at the position of both shins of the passenger. Gas flow paths are disposed within both right and left edge sides of the airbag and can cause the inflating gas flowing at the lower part of the airbag to flow towards the knee protection inflation portion while inhibiting the shin facing portion from greatly inflating in the initial stage of inflation of the airbag.