A replacement filter (14), in particular a spin-on filter, of a filter device (10) for fluid, in particular liquid, in particular oil or fuel, in particular of an internal combustion engine, in particular of a motor vehicle, a filter device and a filter head of a filter device are described. The replacement filter (14) has a filter housing (63) in which at least one filter element (70) is arranged or can be arranged. The replacement filter (14) has a connection body (66) arranged on the end face of the filter housing (63), which is provided with at least one fluid opening (98, 104). The replacement filter (14) has a filter-side connection part (108) of a connection device (22) for releasably connecting the replacement filter (14) with a filter head (12) of the filter device (10). The replacement filter (14) has at least one filter-side locking part (110) of at least one locking device (52) for releasably locking the connection device (22). The filter-side connection part (108) can be releasably connected to the filter head (12) by means of a plugging/rotating movement with respect to a connection axis (26). It can be automatically releasably locked by means of the plugging/rotating movement with a corresponding head-side locking part (50) of the locking device (52). At least one filter-side locking part (110) has at least one filter-side latching section (116) of a latching connection for latching with a head-side latching section (56) of a head-side locking part (50) of the at least one locking device (52) in a locked state. It further has at least one support section (118) on the side of the filter-side locking part (110) that is radially remote from the at least one filter-side latching section (116) with respect to the connection axis (26) for supporting the at least one filter-side locking part (110) against at least one housing-side peripheral section (102) at least in the radial direction at least in the locked state.
