The purpose of this study is to develop a soft tactile sensor which can realize simultaneous measurements of surface shape and texture. We examine the possibility of the tactile sensor based on an ionic polymer-metal composite (IPMC). When tracing a measured object with the IPMC film, the surface shape is estimated from the displacement of the film, and the surface texture is estimated from the vibration of the film. The method for the estimation of displacement was already developed. In this paper, as a preliminary test, the estimation of the roughness of the surface texture was conducted by rubbing waterproof abrasive papers with the IPMC film. The output signals were processed offline, and the pattern classifications based on the frequency analysis were investigated. The differences of the ratio on frequency component of signals were detected against several kinds of the abrasive papers.