Mounting structure for an engine cover

An engine cover panel mounting structure (1) comprises a motor part (3) and a motor cover (2). Several parts to be fastened (7) to which on the motor cover (2) existing fastening parts (17) are to be fixed, are formed so that they are formed below a top of a cylinder head as a cover (3) motor part. In addition, a positioning member (18) to the motor cover (2) is present. In a mount state where a base fastening part (25) fixed or temporarily fixed to a to be fastened to the base part (15), while the other mounting parts (17) not to the other parts to be fixed (7) are fitted, reach, when the engine cover ( 2) to the base mounting portion (25) to rotate until the positioning member (18) engages a surface of the motor part (3) in plant, which is not the base mounting portion (25) forming fastening parts (17) in positions corresponding respectively to be fastened parts ( 7) face.