There is provided a fluid control apparatus which can improve assembling operation efficiency. A screw insertion hole 29 extending in a front and rear direction have a stepped portion 29a which receives a head portion 18a of a male screw member 18, and the stepped portion 29a is positioned at a position closer to an inserted tip end side of a male screw member 28 in the front and rear direction than a position, in the front and rear direction, of male screw members 34 from above. By fastening the male screw member 18 in the front and rear direction at first and then fastening the male screw member 34 from above, it is possible to prevent the male screw member 18 in the front and rear direction and the male screw member 34 from above from interfering with each other.