An electromagnetic shielding device in an infrared receiver comprises of a wiring frame (4) of metal and an electromagnetic shielding cover (1) of metal. There is a window (2) in the electromagnetic shielding cover (1), in which there is provided a shielding net (3). The electromagnetic shielding cover (1) has a protruding tongue (6) in the bottom of its both sides respectively and the protruding tongues (6) are bent downwards and entad to engage on the wiring frame (4), thus forming an electromagnetic shielding structure transparent to a chip inside. The electromagnetic shielding device of the present invention is simple in structure, reasonable in design, easy to manufacture, low-cost, high qualified ratio and thus suitable for mass productivity. The electromagnetic shielding device improves the electromagnetic interference preventive capability of a semiconductor element and thus increases the sensibility and reliability of an infrared receiver.