A cover of a folding-top compartment in a cabriolet vehicle can be pivoted by way of links between a position in which the cover covers the folding-top compartment and a position in which the cover does not cover the folding-top compartment. The recording layer includes a recording magnetic domain in which information is recorded by a magnetization direction vertical to the surface of the film. The damping-force-calculating subunit calculates the damping coefficient by multiplying a returning force calculated in the returning-force-calculating subunit by the required proportionality coefficient and then calculates a damping force by multiplying the obtained damping coefficient by an operation speed of the operating unit. In response to the determined distribution data, the signal processor initiates generation of a message associated with the degree of similarity between the first and second signal portions. Information included in a predetermined section of the response message and all or a predetermined part of identification information designated are compared.