fig1 and 5 the thread guide 17 is formed at the lowest part thereof with a laterally extending projection 32 which is provided at the rear side thereof with a face 31 inclined toward the operator to guide the thread to be inserted into the needle eye the thread is guided to a horizontal groove 33 extending all through the thread guide 17 across a hole 32a through which the threading blade 24 passes and between the guide projection 23 and the base of the lateral projection 32 as particularly shown in fig4 and 5 the needle bar 2 is provided with a stopping pin 30 at its lower part for checking the down movement of the thread guide 17 and positioning the same with respect to the needle eye 4 fig1 the slider 8 is held to the base plate 6 by the holding plate 11 of the spring material and the springs 14 22 press the aforementioned projections 15 and 19 against the plate 6 respectively the threading device is also supported on the base plate 6 with the projection 19 getting over a checking projection 34 provided on the base plate 6 as shown in fig1 therefore the threading device will not be slipped down by vibration of the sewing machine in operation the instant device is of the above mentioned structure which is.