To provide a sealing device capable of retaining a sealing function even if pressure is accumulated in a space between a first seal part and a second seal part.
The sealing device is characterized in that a communication hole 20 having a membrane part 23 provided to block a gap between a first opening 21 opened into a sealed space S and a second opening 22 opened into a low pressure side L and connecting the first opening 21 to the second opening before a pressure of the sealed space S rises to a pressure of a degree causing breakage of the seal lips, when the pressure of the sealed space S rises with respect to a pressure of the low pressure side L, and capable of connecting the sealed space S with the low pressure side L by connecting the first opening 21 to the second opening by the membrane part 23, is provided in a second seal part 12 disposed in the low pressure side L of a first seal part 11 of the sealing device 1 for a fuel pump and having the seal lips 16, 17 slidably contacting a surface 301 of a shaft 300.
EGUCHI NOBUYUKI
Mayuko Wakuda
Koichiro Sakai