A flat-tire repair kit comprising: a bottle containing a flat-tire repair solution; and a bottle attachment portion to which a bottle opening of the bottle is connectable by being relatively rotated to screw the bottle opening and the bottle attachment portion together; wherein the bottle opening includes a sealing member configured to seal the solution inside the bottle, the bottle opening or the bottle attachment portion includes a seal member configured to make a connection of the bottle opening to the bottle attachment portion liquid-tight after the bottle opening starts to be rotated relative to the bottle attachment portion, and the bottle attachment portion includes a sealing-breaker projection configured to contact and break the sealing member after the seal member starts to make the connection liquid-tight, and the bottle opening includes a bottle-side engagement portion configured to engage with an attachment-side engagement portion, included in the bottle attachment portion, after the sealing-breaker projection breaks the sealing member, so as to prevent the bottle opening from relatively rotating in an opposite rotation direction from a rotation direction when the bottle opening is screwed onto the bottle attachment portion, characterized in that when a total rotation angle of relative rotation of the bottle opening relative to the bottle attachment portion is 100 from a start of the bottle opening and the bottle attachment portion being screwed together until the bottle-side engagement portion and the attachment-side engagement portion are engaged, a rotation angle of relative rotation after the start of screwing until the seal member starts to make the connection liquid-tight is 15 to 25 relative to the total rotation angle, the rotation angle of relative rotation after the start of screwing until the sealing-breaker projection contacts the sealing member is 20 to 35 relative to the total rotation angle, and the rotation angle of relative rotation after the start of screwing until the bottle-side engagement portion and the attachment-side engagement portion start to engage is 60 to 95 relative to the total rotation angle. a bottle containing a flat-tire repair solution; and a bottle attachment portion to which a bottle opening of the bottle is connectable by being relatively rotated to screw the bottle opening and the bottle attachment portion together; wherein the bottle opening includes a sealing member configured to seal the solution inside the bottle, the bottle opening or the bottle attachment portion includes a seal member configured to make a connection of the bottle opening to the bottle attachment portion liquid-tight after the bottle opening starts to be rotated relative to the bottle attachment portion, and the bottle attachment portion includes a sealing-breaker projection configured to contact and break the sealing member after the seal member starts to make the connection liquid-tight, and the bottle opening includes a bottle-side engagement portion configured to engage with an attachment-side engagement portion, included in the bottle attachment portion, after the sealing-breaker projection breaks the sealing member, so as to prevent the bottle opening from relatively rotating in an opposite rotation direction from a rotation direction when the bottle opening is screwed onto the bottle attachment portion, characterized in that when a total rotation angle of relative rotation of the bottle opening relative to the bottle attachment portion is 100 from a start of the bottle opening and the bottle attachment portion being screwed together until the bottle-side engagement portion and the attachment-side engagement portion are engaged, a rotation angle of relative rotation after the start of screwing until the seal member starts to make the connection liquid-tight is 15 to 25 relative to the total rotation angle, the rotation angle of relative rotation after the start of screwing until the sealing-breaker projection contacts the sealing member is 20 to 35 relative to the total rotation angle, and the rotation angle of relative rotation after the start of screwing until the bottle-side engagement portion and the attachment-side engagement portion start to engage is 60 to 95 relative to the total rotation angle.