Abstract: Provided is a tire mounted anti-skid apparatus, in which a fixing plate is attached to a tire wheel through adaptors, and a support plate has a plurality of anti-skid arms is fitted to the fixing plate and is fixed on a side of the tire by a locking plate. Each adaptor includes a fix clip having a clip and a cap, and first and second bolts. The clip is fitted around a wheel nut of a wheel of the tire and including six legs separated from one another, a nut hole in a rear thereof, and protrusions, each of which protrudes from a leading end of the leg in an outward direction, and the cap covers the clip, causes an inner circumference thereof to press the protrusions of the clip, and includes a cylindrical cap having a nut hole communicating with the nut hole of the clip in a rear thereof.