To provide a unit valve for an air duct and an accumulation conveyer very easily connected accordingly to prevent complexity of piping and very easily changed between sequential feed function and collective feed function at a very low cost.

This unit valve 90 comprises a first valve part 7a having a first shuttle valve 7 and a second valve part 7a having a second shuttle valve 8. It also includes a third connection port 3 connected with a check valve 73 side of the first shuttle valve 7, a first connection port 1 and a second connection port 2 connected with a reverse check valve side 71 on the opposite side of the check valve 73 of the first shuttle valve 7, a fifth connection port 5 and a sixth connection port 6 connected with a check valve 83 side of the second shuttle valve 8 and a connection port 4 connected with a branch side 84 of the second shuttle valve 8. A branch side 74 of the first shuttle valve 7 and a reverse check valve side 81 of the second shuttle valve 8 are connected with each other.