The invention relates to a vacuum arc-extinguishing chamber and a contact device thereof as well as a conducting rod and a contact of the contact device. The contact device comprises the conducting rod and the contact, wherein the contact is welded and assembled at the front end of the conducting rod through a welding flux between the contact and the conducting rod; a forward blocking surface is arranged at the front end of the conducting rod; a convex column is arranged on the blocking surface; a top pressing surface matched with the blocking surface in a corresponding blocking manner is arranged on the contact; an inserting hole consistent with the convex column in an inserting manner is formed in the top pressing surface; the convex column is provided with a penetrating part which extends forwards and penetrates out of the inserting hole; a clamping groove is formed in the penetrating part; a clamping spring matched with the corresponding blocking surface and top pressing surface so as to realize pre-fixing assembling before the welding of the contact and the conducting rod is clamped in the clamping groove correspondingly; and a forward pressure-bearing surface matched with the clamping spring in a support top pressing manner is arranged on the contact. In the manner of locating in axial direction and radial direction respectively, gaps caused by the fact that the contact is inclined in the fixing process are avoided, and the welding effect is effectively guaranteed.