Since the spread of and high functionality of smartphones, we are dealing with large amounts of data, which include personally identifiable information, in the outdoors almost every day. Accordingly, smartphones are equipped with various personal authentication functions. In this paper, we describe a security enhancement method for pattern authentication of smartphone. This method is one of a biometrics authentication, which is based on locus of figure drawing and angle of device holding. To discriminate individual users, We applied self-organizing maps (SOM) for the authentication. The result suggests the possibility to enhance the accuracy of pattern authentication.