HYDRAULIC DRIVING APPARATUS

A counter balance valve (71L) is located between a directional control valve (23) and a hydraulic motor (32L) and provided on the way of a pair of supply/discharge lines (25A, 25B). The counter balance valve (71L) allows a spool (72L) to be displaced axially based on a pressure difference between the supply/discharge lines (25A, 25B). The counter balance valve (71L) includes a communicating passage (73L) for communicating the supply/discharge lines (25A, 25B) when the displacement of the spool (72L) exceeds a predetermined amount (XCM), based on a pressure difference between the supply/discharge lines (25A, 25B). The communicating passage (73L) is provided in the spool (72L) of the counter balance valve (71L).