A heat insulating cover (cylinder-head-side heat insulating cover (30)) includes a top wall (31) and first side walls (32). The top wall (31) covers a top surface of an engine (1) that is a surface of an upper portion of the engine (1). The first side walls (32) cover respective upper portions of both side surfaces of the engine (1) in a vehicle width direction. A portion of the heat insulating cover closer to the rear of the vehicle is provided with a hinge mechanism (36) vertically rotatably supporting the upper portion of the heat insulating cover including the top wall (31). The upper portion of the heat insulating cover can be rotated, with the hinge mechanism (36) as a fulcrum, between a closed position where the engine (1) is shielded and an open position where the engine (1) is visible.