To prevent a slipper or a sandal from coming off from the foot of a wearer and enable an enough fastening force to be kept by simply, conveniently and easily adjusting a wear opening of a vamp of the slipper or the sandal, easy to put on but prone to come off, to bring the opening into close contact with the foot of the wearer.

Several to tens of straps 3 with several to tens of cm in length are provided respectively on both sides of the periphery of a slipper sole 1 or a sandal sole for a band 4 to be a vamp being simply and conveniently attached/detached and a fastening force of the band being easily adjusted. Thereby, knotting the straps 3 in close proximity or pieces between the straps 3 by the wearer at need generates spaces between the straps and the slipper sole or the sandal sole. The band 4 is inserted into the space and both ends of the band 4 are knot-connected, thereby allowing the band 4, as the vamp of the slipper sole or the sandal sole, to be attached/detached.