A downhole pressure compensating device includes a housing with a chamber and an internal hollow section, a first piston dividing the chamber into a first section and a second section, the first section being in fluid communication with a first fluid port, the second section being in fluid communication with a borehole through a second fluid port, and a first spring disposed within the second section to exert a pressure on the first piston to enable the conservation of an overpressure in the first section. Furthermore, the device includes second piston, a second spring disposed between the first piston and the second piston, and an overpressure channel arranged in the first or the second piston, which overpressure channel, when the second spring is in a compressed condition, provides fluid communication between said first and second sections.