Abstract: In a fluid damper that autonomously changes a damping force in accordance with movement of a piston, the fluid damper having: a fluid 8 having magnetic properties; a piston 2 formed of a magnetic material; a cylinder 3 that encapsulates the fluid 8 having magnetic properties and accommodates the piston 2; a piston rod 4 that pierces the cylinder 3 to support the piston 2; a magnetic field generation device 6 provided outside the cylinder 3; a first yoke 5 arranged around the cylinder 3; and a second yoke 7 arranged around the piston rod 4 outside the cylinder 3, a magnetic circuit is partially formed.