An operating device for a hopper/awning window unit, the window unit comprising a fixed frame and a mobile frame which is rotatably associated with the fixed frame and equipped with at least a lower rail comprising a longitudinal tubular channel extending along a line of extension and comprising a bottom wall formed by a pair of longitudinal plates extending in a parallel fashion along the line of extension and separated by a slot for forming a "C"-shaped cross-section, comprising: - a containment body extending along its own main axis; - an operating element housed in the containment body, which can be associated with a mechanism for locking the window unit, and comprising a first mobile portion, which can be coupled with a handle, and a second mobile portion connected to the first portion and which can be associated with the mechanism; - supporting means for the containment body, which can be associated with the mobile frame at the channel for keeping the operating element connected to the mobile frame and projecting from the channel;said supporting means comprising at least one connecting body fixed to the containment body and comprising a portion with a smaller cross-section, proximal to the containment body, and a portion with a larger cross-section, distal from the containment body, for forming an undercut; the portion with a larger cross-section being at least partly abutable by resting on the plates of the lower wall of the channel, thus preventing the connecting body from passing through the slot; said portion with the larger cross-section of each connecting body being formed by a cam rotatably connected to the containment body for rotating between a first angular position, in which it has a minimum transversal extension and it defines the body insertion configuration, and a second angular position, in which it has a maximum transversal extension and defines the body supporting configuration; characterized in that each cam comprises elastic snap fitting means interposed between the cam and the containment body for holding the cam on the body and designed to allow free relative rotation between the cam and the containment body. - a containment body extending along its own main axis; - an operating element housed in the containment body, which can be associated with a mechanism for locking the window unit, and comprising a first mobile portion, which can be coupled with a handle, and a second mobile portion connected to the first portion and which can be associated with the mechanism; - supporting means for the containment body, which can be associated with the mobile frame at the channel for keeping the operating element connected to the mobile frame and projecting from the channel;said supporting means comprising at least one connecting body fixed to the containment body and comprising a portion with a smaller cross-section, proximal to the containment body, and a portion with a larger cross-section, distal from the containment body, for forming an undercut; the portion with a larger cross-section being at least partly abutable by resting on the plates of the lower wall of the channel, thus preventing the connecting body from passing through the slot; said portion with the larger cross-section of each connecting body being formed by a cam rotatably connected to the containment body for rotating between a first angular position, in which it has a minimum transversal extension and it defines the body insertion configuration, and a second angular position, in which it has a maximum transversal extension and defines the body supporting configuration; characterized in that each cam comprises elastic snap fitting means interposed between the cam and the containment body for holding the cam on the body and designed to allow free relative rotation between the cam and the containment body.