PROBLEM TO BE SOLVED: To provide an automatic peritoneal dialyzer allowing a user such as a patient to obtain a click feeling when the user such as the patient pushes a necessary operation switch to allow the user such as the patient to certainly recognize the pushing.SOLUTION: This automatic peritoneal dialyzer 1 includes: a cassette 100 having a pump feeding a peritoneal dialysate a cassette installation part 20 to which the cassette 100 is detachably installed along an insertion direction and operation switches 11, 12 operated when performing a dialytic prescription. Each of the operation switches 11, 12 includes: a switch element 702 having an operation member and a push member 790 connected to the operation member 720 of the switch element 702 with a preset gap LK, for pushing the operation member 720 of the switch element 702 in such a state that the gap LK is eliminated by being pushed.
