A double ball joint device comprises a housing, a first joint element having a first ball mounted in the housing, and a first shaft attached to a portion of the first ball protruding through an opening in the housing, and a second joint element having a second ball, which is mounted similar to the first ball and is provided with a corresponding second shaft. A locking washer is arranged between the first and second balls and has a first seat for receiving the first ball, and an opposite second seat for receiving the second ball. An operation member is operable between a released state, where the joint elements are pivotable, and a locked state, where it urges the locking washer to clamp lock the joint elements in a current position. When moving the operation member to the locked state it urges the washer to an off-centre position.