Abstract: A pipe connection device for a scientific equipment in which a reduced diameter head having slits is formed at a front end part of a clamp covering a packing fitted to an outer circumference of the open end part of the pipe. A part of the packing is positioned within the reduced diameter head. The reduced diameter head, at its extremity end, forms an inclined cylinder part fitted to an inner inclined surface of the fixed screw and also forms a cylinder part to which a pressing ring is engaged and fitted adjacent to the inclined cylinder part. The reduced diameter head is reduced in its diameter by the inner inclined surface under screwing of the fixed screw. The pressing ring, formed to have a slightly smaller diameter than an outer diameter of the cylinder part, is pressed against an open end surface of the inner inclined surface. The pressing ring is raised up over the inclined cylinder part and press fitted onto the cylinder part.