A slit band sheet coiling-tension applying device, comprising: a first stretched portion configured to include a first belt reversing portion having an arc-shaped outer peripheral surface, and a second belt reversing portion disposed with a predetermined gap between the first belt reversing portion, the second belt reversing portion having an arc-shaped outer peripheral surface formed on an opposite side of a side of the first belt reversing portion; one or more first belts, each of the one or more first belts being configured to be made of materials having different friction coefficients, to have a side with a smaller friction coefficient that is brought into contact with the arc-shaped outer peripheral surfaces (18; 19) of the first belt reversing portion and the second belt reversing portion, and to be stretched in a ring shape to be freely circulated around the first stretched portion; a first pressing portion configured to be provided between the first belt reversing portion and the second belt reversing portion and adjacent to the first belt reversing portion, and to be brought into contact with the side with the smaller friction coefficient of the one or more first belts by a predetermined length; a first tension adjusting portion configured to change a distance between the second belt reversing portion and the first pressing portion; a second stretched portion configured to include a third belt reversing portion positioned to face the first belt reversing portion and having an arc-shaped outer peripheral surface, and a fourth belt reversing portion provided with a predetermined gap between the third belt reversing portion, the fourth belt reversing portion being positioned to face the second belt reversing portion and having an arc-shaped outer peripheral surface formed on an opposite side of a side of the third belt reversing portion; one or more second belts, each of the one or more second belts being configured to be made of materials having different friction coefficients, to have a side with a smaller friction coefficient that is brought into contact with the arc-shaped outer peripheral surfaces (24; 25) of the third belt reversing portion and the fourth belt reversing portion, and to be stretched in a ring shape to be freely circulated around the second stretched portion; a second pressing portion configured to be provided between the third belt reversing portion and the fourth belt reversing portion and adjacent to the third belt reversing portion, and to be brought into contact with the side with the smaller friction coefficient of the one or more second belts by a predetermined length; and a second tension adjusting portion configured to change a distance between the fourth belt reversing portion and the second pressing portion. a first stretched portion configured to include a first belt reversing portion having an arc-shaped outer peripheral surface, and a second belt reversing portion disposed with a predetermined gap between the first belt reversing portion, the second belt reversing portion having an arc-shaped outer peripheral surface formed on an opposite side of a side of the first belt reversing portion; one or more first belts, each of the one or more first belts being configured to be made of materials having different friction coefficients, to have a side with a smaller friction coefficient that is brought into contact with the arc-shaped outer peripheral surfaces (18; 19) of the first belt reversing portion and the second belt reversing portion, and to be stretched in a ring shape to be freely circulated around the first stretched portion; a first pressing portion configured to be provided between the first belt reversing portion and the second belt reversing portion and adjacent to the first belt reversing portion, and to be brought into contact with the side with the smaller friction coefficient of the one or more first belts by a predetermined length; a first tension adjusting portion configured to change a distance between the second belt reversing portion and the first pressing portion; a second stretched portion configured to include a third belt reversing portion positioned to face the first belt reversing portion and having an arc-shaped outer peripheral surface, and a fourth belt reversing portion provided with a predetermined gap between the third belt reversing portion, the fourth belt reversing portion being positioned to face the second belt reversing portion and having an arc-shaped outer peripheral surface formed on an opposite side of a side of the third belt reversing portion; one or more second belts, each of the one or more second belts being configured to be made of materials having different friction coefficients, to have a side with a smaller friction coefficient that is brought into contact with the arc-shaped outer peripheral surfaces (24; 25) of the third belt reversing portion and the fourth belt reversing portion, and to be stretched in a ring shape to be freely circulated around the second stretched portion; a second pressing portion configured to be provided between the third belt reversing portion and the fourth belt reversing portion and adjacent to the third belt reversing portion, and to be brought into contact with the side with the smaller friction coefficient of the one or more second belts by a predetermined length; and a second tension adjusting portion configured to change a distance between the fourth belt reversing portion and the second pressing portion.