To make a line head chassis detachable simply and easily in an inkjet recording apparatus, a jig for the line head chassis is provided which comprises: a first support member mounted on a table lateral to the inkjet head; a second support member mounted laterally to and lower than the first support member; a rail member mounted laterally to the first support member and having one end connected thereto; an upright support member having its lower end supported by the second support member adjustably in its height direction and its upper end connected to the other end of the rail member for supporting the rail member horizontally; a base table slidably supported on the rail member to move over a distance outward from a maintenance position; and a cradle means supported on the base table so as to be movable perpendicularly to a direction in which the base table moves for accepting the line head chassis, wherein one end of the rail member and the lower end of the upright support member are made engageable with/disengageable from the first and second support members, respectively.