To provide a member for mounting a disposable toilet seat cover that keeps a toilet seat clean without soiling the lower surface of the toilet seat even when excrement splashes on the lower surface of the toilet seat after excretion, the disposable toilet seat cover, and a toilet seat cover storage unit.

The member for mounting a disposable toilet seat cover is configured to allow mounting of a disposable toilet seat cover 1, formed of a water-soluble sheet, to a toilet seat 102 of a sitting toilet bowl 100. The member has: an elastically-deformable base material 2f or 3f; a fixing layer 2d or 3d formed on one surface of the base material 2f or 3f and fixable to the toilet seat 102; and an adhesive layer 2e or 3e formed on the other surface of the base material 2f or 3f and peelably sticking the disposable toilet seat cover 1 to the toilet seat. The member can be fixed to one surface (the upper surface or the lower surface) of the toilet seat 102.