To provide a lightweight and easily assembled soundproof cover by forming the soundproof cover into a two-piece structure body of a front cover and a rear cover, and integrally molding both covers out of a synthetic resin by respectively installing metallic skeletons to function as strength members on the inside.

A soundproof cover to cover the outside of a portable engine generator is formed into a two-piece structure composed of a front cover 4 and a rear cover 5, and a bottom plate 7 is integrally formed on the front cover 4. These front and rear covers 4 and 5 are formed of a section using a synthetic resin as a material, and plural metallic skeletons 6 are molded on the inside of them by integral molding in a condition of reinforcing the synthetic resin covers 4 and 5. When the front cover 4 and the rear cover 5 are assembled, after a main unit is fixed on the bottom plate 7 by using a bolt of the bottom plate 7, in a condition where a mating face 5A of the rear cover 5 is brought into contact with the front cover 4, a bolt 17 is inserted from a front wall side through hole of the front cover 4, and is screw-fitted to a screw hole 64 of the rear cover 5.