A fluid control device manifold includes a first body, a second body, and a connection part configured to interpose a seal member between the first and second bodies and allow a connecting tool to engage with engagement surfaces of the bodies. When a load is applied to the engagement surfaces to draw the first and second bodies close to each other, the seal member is press-fitted into the bodies. This press-fitted state is held by a clamp. One or both of the first and second bodies are internally provided with a plurality of the engagement surfaces extending in a nearly perpendicular direction to a drawing direction.