To provide a toilet seat sheet feeder using a backrest capable of avoiding a problem that, when a plurality of users use toilet seat sheets, it has still a sanitary problem and gives a user an unsanitary feeling, and allowing the user to simply use a comfortable toilet seat sheet.

This toilet seat sheet feeder using the backrest is provided with the backrest disposed in the back of the toilet seat, hollow parts for toilet seat sheets formed in the backrest for storing the toilet seat sheets, a toilet seat sheet moving means for reciprocating the toilet seat sheets between the positions on the toilet seat and the positions inside the hollow parts for the toilet seat sheets, and a toilet seat sheet moving control means for controlling the toilet seat sheet moving means.