PURPOSE: To improve appearance at the time of mounting and save a space, by inserting a screw rod into a screw hole penetrating from the surface to the rear of an electronic unit in the manner in which two electronic units are related.

CONSTITUTION: In an electronic unit 1, a screw hole 14 having specified screw diameter and screw pitch is formed so as to penetrate the unit from the surface to the rear. On the whole outer peripheral surface of a screw rod 20, a screw part 15 provided with the screw diameter and the pitch corresponding with the screw hole 14 is formed. An unit mount part 30 mounts a plurality of the electronic units 1 in the state of lamination by using the screw rodes 20. In this mount structure, the electronic units 1 are mounted by screwing the screw rods 20 in the screw holes 14 penetrating each of the electronic units 1, in the manner in which two of the electronic units 1 mounted in the state of lamination are related. Thereby a special rack for mount, linkage metal fittings, etc., are made unnecessary, so that apperance is improved and a space can be saved.