The invention relates to a seat fastening device, especially for fastening aircraft passenger seats to the cabin deck of an aircraft, which has at least one fastening rail (12) which is provided on its top facing the passenger seat with through openings (14) which have distances to one another in a definable grid and which are used for passage of catch parts (16) of a locking body (10), and for detachable fastening of the locking body (10) to the fastening rail (12) from a release position into a locking position the respective catch parts (16) can be inserted into the assignable through openings (14) and can be at least partially triggered by an actuating means. Because in the release position the respective catch parts (16) point in one direction and because in the locking position at least one of the catch parts (16) is pivoted by the actuating means (28) such that it extends under the parts (24) of the fastening rail (12), the existing devices and systems are further improved such that the mounting effort on site can be reduced and the advantages of the fastening device as claimed in the invention become apparent especially for frequent installation and modification measures.