Owing to the combination of wheel feed and driven roller presser, no wrinkle in light material and fine stitch in heavy material. Maintenance-free ball and needle bearing and link take-up lever. Applied full-revolution vertical rotary hook with positive bobbin case opener. Equipped with easy-operating safety clutch which would protect rotating hook from damage. For sewing functional and emmental seams preferably on concave portions of shoe uppers, leather products, etc. Accurate and uniform setting of stitches and infinite stitch length variation. Applied with large hook ensures high sewing efficiency.