This paper proposes a new tactile sensor capable of automatically adjusting the sensitivity of each sensor unit, depending upon the contact information. Suppose a strain gauge based tactile sensor composed of multiple sub-sensor units and a single AD-DA port. For such a sensor system, we introduce two key components; the Analyzer, how to determine the contact force quickly from each sub-sensor unit, and the automatic gain controller (AGC), how to automatically change the gain for each unit, according to the sensory information. For example, the sensor can automatically cope with both the signal saturation due to an unexpectedly large input and the resolution control depending upon the contact force. The basic idea of the sensor system is verified by experiments.