To cause oil to be easily supplemented and also easily replaced with new one in a hydraulic operating machine in which a supplying means for supplying oil into a cylinder chamber so as to prevent occurrence of negative pressure within a hydraulic circuit for a tool when a movable tool is moved is installed in a head frame.

A hydraulic operating machine is comprised of a main body A of the operating machine provided with a head frame 5 and a cylinder chamber 13 to which a fixed machining tool 35 is fixed, and a piston B which is slidably arranged within the cylinder chamber 13 and to which a movable machining tool 33 is fixed, and a supplying means 46 for supplying oil into the cylinder chamber 13 when the movable machining tool 33 is moved. The supplying means 46 is comprised of a bag body 47 which is inserted into a storing hole part 45 of the head frame 5 and having its opening communicated with the cylinder chamber 13 through a hydraulic pump 17.