The invention relates to a fluid filter including a filter socket with a mounting flange that can, in a sealing manner, be connected to a companion flange on an associated apparatus, wherein at least one fluid duct for supplying fluid to be filtered and one fluid duct for discharging filtered fluid extends through the flange connection, wherein, in the filter socket, at least one section of at least one fluid duct can be closed off against the companion flange by means of a sealing plate designed with at least one through opening that is sealed against the companion flange and is arranged flush with an apparatus-side fluid duct. Therein, it is provided that the surface area of the sealing plate, as seen on the plane of the flange connection, is smaller than the surface area of the mounting flange and that the sealing plate is inserted in the filter socket in a sealing manner and forms a part of the filter socket.