This manufacturing method for a fluid control apparatus, in which the flow of a fluid is controlled by bringing a diaphragm valve element into contact with or separating the same from a valve seat, is characterized in that: the diaphragm valve element is a joint body of a seat member making contact with the valve seat and a body member; the joint body is formed by cutting a material joint body obtained by depositing a seat member material which is a material for the seat member and a body member material which is a material for the body member, and the deposition is performed over a wider range than a contact surface between the seat member and the body member of the joint body, on the contact surface between the seat member material and the body member material of the material joint body.