Provided are a cleaning sheet and a cleaning tool which have improved usability. The cleaning sheet is attachable to a cleaning-sheet mounting member. The cleaning sheet has a center section made up of a cleaning surface and at least one end section disposed at one or more sides with respect to the center section in a predetermined direction. The end section has a first portion having a first elongation percentage and a second portion having a second elongation percentage which is higher than that of the first portion. The second portion is disposed in said direction between the first portion and the center section and is constructed so as to be supported by the cleaning-sheet mounting member at the boundary between the first and second portions. The cleaning tool is provided with the cleaning sheet.