Conventionally, a technique is known which can recognize user's gesture by analyzing sensor data of an acceleration sensor and the like. A user can input a command in accordance with the gesture by moving a finger on an arbitrary operation surface by using this recognition technique. As a method for recognizing a gesture on the arbitrary operation surface, a method is proposed in which a signal by pressing down, tracing, and lifting a finger wearing a sensor.
However, in the above-described conventional gesture recognition method, it is difficult to correctly recognize a gesture since the gesture on an operation surface is incorrectly recognized in the case of incorrectly detecting pressing down and lifting a finger.