the electronic parts on the bottom of the circuit board 50 the insertion terminals 106 to the female connectors 33 of the mother board 32 and so on the second noise shield sheet 56 is mounted on the bottom of the circuit board 50 each of the insertion hole 118 of the second noise shield sheet 56 includes a first insertion hole 120 which is formed through the shield layer 116 and finished by etching the punched portions therein and a second insertion hole 122 which is punched through the insulating layer 114 within the portion of the first insertion hole 120 having no shield layer 116 at a portion of the shield layer 116 remote from the edge of the first insertion hole 120 with provision of the first and second insertion holes 120 122 in such a manner the first insertion hole 120 will be larger than the second insertion hole 122 when the electronic parts and insertion terminals 106 are inserted through the insertion holes 118 these parts may contact the edge of the second insertion holes 122 but not contact the first insertion holes 120 larger than the second insertion holes 122 as a result any short circuiting between the conductive shield layer 116 and the terminals of the electronic parts can be reliably avoided this means that the assembly can be more easily made without need of any accurate position in the second noise shield sheet 56 this embodiment includes a recess 80 opened to the top of a thick walled.