To provide a fluid cargo handling device which is easily balanced even when fluid is kept in or discharged from a pipe in an arm.

In a loading arm 1 having a rise pipe 3, an inboard arm 2 and an outboard arm 7, a two-axis swivel joint 5 is provided on an upper end of the riser pipe 3 fixed to a base 50, and a balance arm 4 extends from a rear end of the inboard arm 2 turnable around the horizontal axis and the perpendicular axis. A balance weight 12 movable around the axial direction of the balance arm 4 is disposed, and a balance adjustment mechanism 11 is provided to move the balance weight 12. The center of gravity is balanced by moving the balance weight 12 according to the fluctuation of the position of the center of gravity of the loading arm 1.