To obtain a compsn. having excellent wet-friction property, wear resistance, and rubber hardness and besides having little toxic components, by blending it with a processing oil comprising a non-aromatic oil and a resin component comprising one of an aromatic hydrocarbon, a petroleum resin, etc.

A processing oil comprising a non-aromatic oil, e.g. a paraffinic oil or a naphthenic oil, pref. having a polycyclic, aromatic compd. content of less than 3 wt.%, is blended with a resin component comprising a resin of an aliphatic hydrocarbon resin, a petroleum resin, a rosin derivative, a cumarone resin, and a phenol terpene resin, pref. an aliphatic hydrocarbon resin, a rosin derivative or a petroleum resin. The non-aromatic oil has pref. a dynamic viscosity at 100°C of 16 cSt or less, and a carbon type ratio, in the aromatic ring part, of 15% or less. A raw material rubber of 100 pts.wt. is blended pref. with the processing oil of 5-70 pts.wt. and the resin component of 5-50 pts.wt.