A ROPS canopy of a hydraulic shovel (hydraulic excavator) is commonly usable among various models regarding different automobile ranks. To configure this, a ROPS canopy (50A) in which two columns (31, 32) support a roof structure (40) is predefined as a basic type ROPS canopy, and the basic type ROPS canopy (50A) is so configured that at least an additional column (51, 52, 53, 54, 55, 56) can be attached such that the basic type ROPS canopy (50A) can be adapted to a ROPS canopy of higher class model. The additional columns (51, 52, 53, 54, 55, 56) are installable (57, 58b) by merely an add-on method.