The present subject matter relates to a filter device (10) for filtering a fluid, in particular of a motor vehicle, comprising a filter housing (12, 14) and a filter element (24, 40) to be coupled thereto, wherein an electrical signal device (50, 52, 64, 66, 68, 70, 72) is provided for detecting the presence of a proper filter element, which comprises at least one electrical signal transfer unit (52, 64, 66) between the filter housing (12, 14) and the filter element (24, 40). According to the present subject matter, the at least one electrical signal transfer unit (52, 64, 66) is configured with at least a sectional circular conductor path (64).
