A toilet seat sheet configured so that a plurality of the toilet seat sheets are accommodated in a packaging bag so as to be taken out therefrom, the toilet seat sheet comprising: a rectangular shaped sheet having a size capable of covering a toilet seat surface and an open hole or an open hole forming portion to be served as an excretion hole formed in a central portion of the sheet, wherein: folding lines (11, 11) extending in a longitudinal direction of the sheet are provided at both side portions of the sheet sandwiching a center line provided at a central portion of the sheet in a widthwise direction of the sheet, the folding lines (11, 11) being arranged at positions each bisecting or nearly bisecting a width between the center line and a right or left side edge, both the side portions are initially folded inward in half along the folding lines to form an initially folded sheet having a vertically long rectangular shape, characterised by a lower half portion of the initially folded sheet divided by a first folding line extending in the widthwise direction provided at a position bisecting or nearly bisecting the vertically long rectangular shape is secondary folded along the first folding fine in half so as to overlap an upper half portion of the initially folded sheet with the right and left side edges of the non-folded sheet facing each other, a lower half portion of the secondary folded sheet divided by a second folding line extending in the widthwise direction provided at a position bisecting or nearly bisecting a rectangular shape formed by the secondary folding is folded along the second folding line in half so as to overlap a rear surface of an upper half portion of the secondary folded sheet, and certain length portions of an end portion that constitute a lower edge portion when the sheet originally takes a vertically long rectangular shape are folded along oblique folding lines so that a central portion of the certain length portions in the widthwise direction forms an apex of a triangle. a rectangular shaped sheet having a size capable of covering a toilet seat surface and an open hole or an open hole forming portion to be served as an excretion hole formed in a central portion of the sheet, wherein: folding lines (11, 11) extending in a longitudinal direction of the sheet are provided at both side portions of the sheet sandwiching a center line provided at a central portion of the sheet in a widthwise direction of the sheet, the folding lines (11, 11) being arranged at positions each bisecting or nearly bisecting a width between the center line and a right or left side edge, both the side portions are initially folded inward in half along the folding lines to form an initially folded sheet having a vertically long rectangular shape, characterised by a lower half portion of the initially folded sheet divided by a first folding line extending in the widthwise direction provided at a position bisecting or nearly bisecting the vertically long rectangular shape is secondary folded along the first folding fine in half so as to overlap an upper half portion of the initially folded sheet with the right and left side edges of the non-folded sheet facing each other, a lower half portion of the secondary folded sheet divided by a second folding line extending in the widthwise direction provided at a position bisecting or nearly bisecting a rectangular shape formed by the secondary folding is folded along the second folding line in half so as to overlap a rear surface of an upper half portion of the secondary folded sheet, and certain length portions of an end portion that constitute a lower edge portion when the sheet originally takes a vertically long rectangular shape are folded along oblique folding lines so that a central portion of the certain length portions in the widthwise direction forms an apex of a triangle. folding lines (11, 11) extending in a longitudinal direction of the sheet are provided at both side portions of the sheet sandwiching a center line provided at a central portion of the sheet in a widthwise direction of the sheet, the folding lines (11, 11) being arranged at positions each bisecting or nearly bisecting a width between the center line and a right or left side edge, both the side portions are initially folded inward in half along the folding lines to form an initially folded sheet having a vertically long rectangular shape, characterised by a lower half portion of the initially folded sheet divided by a first folding line extending in the widthwise direction provided at a position bisecting or nearly bisecting the vertically long rectangular shape is secondary folded along the first folding fine in half so as to overlap an upper half portion of the initially folded sheet with the right and left side edges of the non-folded sheet facing each other, a lower half portion of the secondary folded sheet divided by a second folding line extending in the widthwise direction provided at a position bisecting or nearly bisecting a rectangular shape formed by the secondary folding is folded along the second folding line in half so as to overlap a rear surface of an upper half portion of the secondary folded sheet, and certain length portions of an end portion that constitute a lower edge portion when the sheet originally takes a vertically long rectangular shape are folded along oblique folding lines so that a central portion of the certain length portions in the widthwise direction forms an apex of a triangle.