PROBLEM TO BE SOLVED: To easily connect a filter to be used in a dialyzer or the like to a holder.SOLUTION: A holder 1 includes an inflow side connection part 20 and an outflow side connection part 30 into and to which an inflow tube part F11 and an outflow tube part F12 of a filter F are pressed and connected, and includes a hand hooking part 40 on which a connection operator hooks a hand between the inflow side connection part 20 and the outflow side connection part 30. During connecting the filter F to the holder 1, when force is added so as to grip a housing F1 and the hand hooking part 40 together with a palm placed on the housing F1 and with a finger hooked on the hand hooking part 40 while making the inflow tube part F11 and the outflow tube part F12 of the filter F face the inflow side connection part 20 and the outflow side connection part 30, respectively, force in a direction where the housing F1 approaches the holder body 10 acts to push the inflow tube part F11 and the outflow tube part F12 into the inflow side connection part 20 and the outflow side connection part 30 to be connected.
