A valve structure includes a partition wall, a communicating bore, a valve body and a restraining portion. The partition wall is provided in a fluid container for dividing the fluid container into a first fluid chamber and a second fluid chamber. The communicating bore is provided at the partition wall for establishing a fluid communication between the first and second fluid chambers. The valve body is provided at the partition wall for establishing and interrupting the fluid communication between the first and second fluid chambers. Further, the valve body includes an umbrella shaped valve portion being flexibly deformable for opening and closing the communicating bore. The restraining portion is provided for restraining a deforming amount of the valve portion when the valve portion is deformed in a direction to be separated from the partition wall.