The disclosure relates to a pendulum suspension device (1) of a spray boom (2), comprising: a fixed frame (3) intended to be borne by an agricultural machine, a mobile frame (4) intended to bear one or several spray booms (2), a pendulum suspension connecting rod (5) connected pivotably in an upper pivot point (7) to the fixed frame (3), said connecting rod (5) connected pivotally in a lower pivot point (8) to the mobile frame (4), and at least one actuation cylinder (6) in order to displace a center of gravity for the mobile frame (4) including the spray boom (2) relatively to said fixed frame (3), said actuation cylinder (6) is interposed between said mobile frame (4) and said connecting rod (5), the pendulum suspension device (1) further comprising a pair of pendulum cylinders (9, 10) placed on each side of the connecting rod (5), and connected between the fixed frame (3) and the mobile frame (4), where the pendulum cylinders (9, 10) is hydraulically connected by a hydraulic interconnection (19) and is configured for dampening movement of the fixed frame (3) in relation to the mobile frame (4) via a throttle (15) placed in the hydraulic interconnection (19). The disclosure further relates to a method of aligning or correcting a pendulum suspension device (1) of a spray boom (2).