A flexible electrostatic adhesive device was modified successfully to improve an aging characteristics. The experimental results using a previous electrostatic adhesive device has shown that, in concrete wall, the maximum adhesive force was 1kgf or more during applied voltage 10kV. However, problems that the adhesive force decreases depending on aging arose. To solve the problem, the design of the electrostatic device was modified. Thereby, the electrostatic adhesive device succeeded that an adhesive force was generated 1kgf or more during a month or more. The flexible electrostatic adhesive device is useful for a practical use to stick to an inspection apparatus on a concrete wall of a bridge or a tunnel.