To improve the attachment or detachment operation of electric parts for an engine and protect the electric parts from vibrations of the engine by fixing the electric parts and a case cover to the body of an electric parts case with no use of fastener members such as screws and bolts.

An electric parts installation structure for an outboard engine comprises a freely-opened or closed, box-like electric parts case 38 adapted to be disposed on an engine, in which case an electric part 42 is detachably housed. The electric part 42 is housed in the electric parts case 38 while being covered by a cushion holder 44 made of elastic material. The cushion holder 44 is designed in its outer dimension to closely contact with the inner surfaces of the electric parts case 38 at its outer surfaces at the housing state.