Provided is a head assembly for a water purification filter, which includes a head body, a rotation shaft, and a fastening cap. In particular, the rotation shaft is rotated in the state of being placed on a seat protrusion formed on the head body, and a lower seal member is disposed in the portion where the rotation shaft is placed on the seat protrusion. Accordingly, there can be prevented a problem in which the lower seal member departs from a predetermined location during the coupling of the rotation shaft to the head body so that defective assembly occurs.