Valve device

A valve device, comprising:

• a housing in which a valve chamber configured to communicate with an inside of a fuel tank on a lower side and a ventilation chamber configured to communicate with an outside of the fuel tank on an upper side are provided via a partition wall, and an opening portion through which the valve chamber and the ventilation chamber are to communicate with each other is formed in the partition wall;
• a float valve slidably accommodated in the valve chamber;
• and
• a seal member disposed on an upper side of the float valve and configured to close the opening portion, wherein
• the opening portion includes
• a first region, and
• a second region extending in a slit shape from the first region and forming an end portion of the opening portion,
• the seal member includes
• a first cover portion covering the first region, and
• a second cover portion extending from the first cover portion so as to cover the second region,
• the second cover portion includes
• a support portion disposed on a tip end side in an extending direction of the second cover portion and configured to retain and support the seal member with respect to the float valve,
• a wide portion disposed on a base end side in the extending direction with respect to the support portion, and
• a narrow portion provided on a base end side in the extending direction with respect to the wide portion and formed to be narrower than the wide portion, and
• in a state where the seal member is retained and supported by the support portion with respect to the float valve, a width of the wide portion is set such that a tip end of the second region is covered, and that the second region of the opening portion is not exposed out of the seal member even in a state where the seal member is maximally displaced in a radial direction and/or a peripheral direction of the housing with respect to the opening portion.