Abstract: A floating roof-type oil-tank sealing device wherein an inclined connector extends between an upper portion of a seal shoe and the lower portion of outer rim of a floating pontoon, and in such a state that each end of the inclined connector is pivotally supported by means of an inserted pin. A compression spring applies pressure to the inclined connector, thereby causing the seal shoe to slidably contact the peripheral tank wall. A seal member is provided between the outer rim of the pontoon and seal shoe in contact with the level of a stored oil. One end of a weather hood is fixed to the upper portion of the seal shoe, and the other end of the weather hood is made to slide along the surface of an inclined guide provided at the edge of the upper plate of the pontoon.