PURPOSE: To reduce the danger of modification and forgery or the like by detecting information according to the electrostatic guiding effect of a conductive member by using an information member covering the conductive member, which shape is corresponding to the information, with an inconductive member.

CONSTITUTION: An electric field generating means 5 equipped with a pulse generator 8 and a potential detecting means 7 for an electric field are arranged so as to have a latent electrostatic coupling space, and an information member 1 covering a conductive member 3 having the shape corresponding to information with inconductive members 2 and 4 is passed through this electrostatic coupling space. According to the electrostatic guiding effect of a potential from the electric field generating means 5, the information to be transmitted to the potential detecting means 7 is detected corresponding to the shape of the conductive member 3. At one of the electric field generating means 5 and the potential detecting means 7 at least, a guard electrode 6 is provided not to generate the electrostatic coupling space and it is preferable to improve detection sensitivity by generating the latent electrostatic coupling space. Thus, invisible and individual information free from the danger of modification and forgery or the like can be applied at low cost, and identification can be easily automated.