Experiments were made to obtain information on the role of friction in instability of superconducting coil. We constructed a pin slide type device for friction test which works at cryogenic temperature. The pin slides on the inner most part of the coil wound by Nb-Ti-Zr-Ta conductor. The effect of load and sliding velocity on the friction behavior was examined. The minimum friction energy rate for quenching of the superconducting coils was estimated as a function of friction and magnet operation conditions.