To provide a steering axle for a special vehicle capable of enhancing the durability of bearings.

Seal members 41, 42, 43 are installed in at least one of the places between the lower support plate 20D of a steering housing 1 and the lower part of a knuckle 3, between the upper support plate 20U of the steering housing 1 and the upper part of the knuckle 3, and between the upper surface of the upper support plate 20U and the top of a king pin 2. Therefore, at least one of the places can be sealed certainly owing to the sealing action of the seal members 41, 42, 43. This allows certainly preventing dust, earth and sand, etc., from intruding into those places and also lessening of the grease leaking there, at least from one place of the three places. Accordingly the lifetimes of an upper and a lower needle roller bearings 16U and 16D and a thrust ball bearing 17 can be prolonged.