To reduce the labor of an operator by automating the replacement of a filter body.

In the milking facilities, the filter body 7 which filters milk is mounted detachably on a milk sending path 3 which sends milk pumped by a milking means 1 to a storage means 2. Plural filter passage parts 8 which distribute the milk through the filter body 7 are formed in a freely selectable state so that filter flow passage switching means 9 links one of the filter flow passage parts 8 with the milk sending path 3 and does not link others. A control means C operates the filter flow passage switching means 9 according to a flow passage switching command so that the commanded filter flow passage part 8 communicates with the milk sending path 3.