A full rotary hook unit is provided below a needle plate of a sewing machine and is provided with an outer hook having a beak rotating integrally with a lower shaft in synchronization with a vertical movement of a sewing needle and a middle hook rotatably supported by the outer hook. A needle guide element that guides the sewing needle as well as adjusting the clearance between the sewing needle and the beak is formed independent of the outer hook and the middle hook. A position adjustment mechanism is provided that mounts the needle guide element on the outer hook or an element rotating integrally with the outer hook so as to allow adjustment of the positioning of the needle guide element in an axial direction of the lower shaft, thus allowing the clearance between the sewing needle and the beak to be readily adjusted.