A stepless variable auto stroke hydraulic breaker system comprising: a stepless variable auto stroke hydraulic breaker including a cylinder, a piston that is housed in the cylinder to axially reciprocate in the cylinder and is provided with a first piston face that is directed such that an applied pressure acts in a return stroke direction, a second piston face directed such that the applied pressure acts in a working stroke direction, and a circumferential recess located between the first piston face and the second piston face, a pressure conduit that provides a working pressure through a first outlet connected to the cylinder, a reduced pressure return conduit that reduces a pressure through a second outlet connected to the cylinder, and a control valve in which a control plunger is located and which is provided with a small control plunger face for moving the control plunger to a return stroke position and a large control plunger face for moving the control plunger to a working stroke position; a vibration sensor configured to detect vibrations generated when a chisel breaks rocks; a transmitter provided with the vibration sensor and configured to transmit signals generated from the vibration sensor; a receiver configured to receive the signals transmitted from the transmitter; characterized in that: the stepless variable auto stroke hydraulic breaker is controlled by a reception micro controller unit of the receiver, and in that the stepless variable auto stroke hydraulic breaker further includes: a stroke valve, an input side of which is connected to the pressure conduit connected to a hydraulic pump by a stroke control pressure conduit, an output side of which is connected to a switching conduit for the control valve by an additional conduit connected to the control valve, and a lower side of which is connected to the hydraulic pump by a flow rate control valve operated under the control of the reception MCU; and a spring that is installed on an upper surface of the stroke valve to provide a mechanical resetting function according to a change in hydraulic pressure. a stepless variable auto stroke hydraulic breaker including a cylinder, a piston that is housed in the cylinder to axially reciprocate in the cylinder and is provided with a first piston face that is directed such that an applied pressure acts in a return stroke direction, a second piston face directed such that the applied pressure acts in a working stroke direction, and a circumferential recess located between the first piston face and the second piston face, a pressure conduit that provides a working pressure through a first outlet connected to the cylinder, a reduced pressure return conduit that reduces a pressure through a second outlet connected to the cylinder, and a control valve in which a control plunger is located and which is provided with a small control plunger face for moving the control plunger to a return stroke position and a large control plunger face for moving the control plunger to a working stroke position; a cylinder, a piston that is housed in the cylinder to axially reciprocate in the cylinder and is provided with a first piston face that is directed such that an applied pressure acts in a return stroke direction, a second piston face directed such that the applied pressure acts in a working stroke direction, and a circumferential recess located between the first piston face and the second piston face, a pressure conduit that provides a working pressure through a first outlet connected to the cylinder, a reduced pressure return conduit that reduces a pressure through a second outlet connected to the cylinder, and a control valve in which a control plunger is located and which is provided with a small control plunger face for moving the control plunger to a return stroke position and a large control plunger face for moving the control plunger to a working stroke position; a vibration sensor configured to detect vibrations generated when a chisel breaks rocks; a transmitter provided with the vibration sensor and configured to transmit signals generated from the vibration sensor; a receiver configured to receive the signals transmitted from the transmitter; the stepless variable auto stroke hydraulic breaker is controlled by a reception micro controller unit of the receiver, and in that the stepless variable auto stroke hydraulic breaker further includes: a stroke valve, an input side of which is connected to the pressure conduit connected to a hydraulic pump by a stroke control pressure conduit, an output side of which is connected to a switching conduit for the control valve by an additional conduit connected to the control valve, and a lower side of which is connected to the hydraulic pump by a flow rate control valve operated under the control of the reception MCU; and a spring that is installed on an upper surface of the stroke valve to provide a mechanical resetting function according to a change in hydraulic pressure. a stroke valve, an input side of which is connected to the pressure conduit connected to a hydraulic pump by a stroke control pressure conduit, an output side of which is connected to a switching conduit for the control valve by an additional conduit connected to the control valve, and a lower side of which is connected to the hydraulic pump by a flow rate control valve operated under the control of the reception MCU; and a spring that is installed on an upper surface of the stroke valve to provide a mechanical resetting function according to a change in hydraulic pressure.