The invention provides a decorative cover structure for a construction machine, wherein the construction machine comprising a tank is adapted to allow a worker to ascend to and descend from the upper surface of the tank with a decorative cover covering the side surface of the tank and devised such that the worker does not step on the decorative cover. Meanwhile, the cost of the construction machine is reduced. The upper part of the decorative cover (11) is formed as a tilt surface (11e) having a tilt angle on which a worker ascending to and descending from the upper surface (7a) of the fuel tank (7) can not step, and the position of the upper end of the tilt surface (11e) is set to a position depressed from the upper surface (7a) of the fuel tank (7) so that the worker cannot step on the decorative cover (11).