An apparatus for supporting an working head, comprising: - a first frame (2) provided with means for the connection to a self-propelled driving machine； - a second frame (3) connected to the first frame (2)； - first moving means (5) arranged and acting between said first frame (2) and said second frame (3), adapted to translate the second frame (3) bi-directionally with respect to the first frame (2)； - a carriage (4) provided with support and connection means (41, 42) for a working head； - second moving means (6) arranged and acting between said second frame (3) and said carriage (4), adapted to translate the carriage (4) bi-directionally with respect to the second frame (3) by a value corresponding to the extension in this direction of said second frame (3).
