A pressure regulating valve has a first pressure deformation portion connected to and receiving a pressure on a fuel demand side, a second pressure deformation portion opposed to the first pressure deformation portion and receiving a predetermined pressure, first and second flow passages, and a communication passage communicating the first and second flow passages to each other. A valve member has a connecting portion connecting the first and second pressure deformation portions together, and has a valve element provided at the connecting portion and configured to close the communication passage when moved toward the second pressure deformation portion. When the pressure on the fuel demand side is lower than a predetermined value, the valve element does not close the communication passage, but when the pressure on the fuel demand side is equal to or higher than the predetermined value, the valve element closes the communication passage.