A variable capacitance unit is formed between one portion of a human body and an opposed electrode facing it through a casing of a robot toy (electronic device) when the one portion of the human body such as a hand or a finger approaches the surface of the casing of the robot. Since the capacitance of the variable capacitance unit varies according to the facing area and the facing distance of the one portion of the human body and the opposed electrode, it is possible to detect the one portion of the human body approaching or touching the robot toy by detecting this change. Since the opposed electrode forming the touch sensor can be provided within the casing, the touch sensor cannot be seen directly from the outside of the robot toy.