To provide a surface treating agent for a vulcanized rubber, which satisfies performances required to a coating agent for a rubbery elastomer etc., such as anti-fixation, anti-adhesion, anti-blocking and wear-resistance improvement and prevents peeling of a coating film caused by adhesion at hot-pressing or frictional wear under a high contact pressure.

The coating agent comprises (a) a cellulose derivative, (b) 1,2-polybutadiene containing an isocyanate group and (c) at least one chosen from a wax having a softening point of 40-160C, graphite and a fluororesin.