To provide a damper device that can extend length even when not performing extension and contraction vibration presently.

The damper device 1, which generates a damping force by dividing the interior part of a cylinder 2 by a piston 3 into a first fluid room 2a and a second fluid room 2b, includes: a piston rod 4, one end of which is connected to the piston 3, the other end of which is extended outside the upper end side of the cylinder 2, and in which a third fluid room 4a is provided; a pump rod 5, one end of which is fixed on the lower end side of the cylinder 2, the other end of which is arranged in the third fluid room 4a, in which a fluid passage 5a penetrating in the axial direction is provided, and which performs the pumping operations of repeating suction and discharge when vibrating to the third fluid room 4a; a first chamber 8, the internal pressure of which rises with the inflow of a working fluid 12 when discharged; a second chamber 9, the internal pressure of which decreases with the outflow of the working fluid when sucked; and a first switching means 10, which switches the states that the second fluid room 2b is communicated and not communicated with the first chamber 8.