Abstract: An upper feed mechanism of a sewing machine, in which a horizontal motion mechanism for moving the upper feed dog back and forth is provided with a double lever mechanism composed of a single arm lever, a bifurcate lever and a slider slidably mounted on both levers, and a crank lever mechanism for oscillating the levers. When a crank of the crank lever mechanism is at a top dead point or a bottom dead point, the radial directions of the levers are matched, and when the slider is moved in this state, the upper feed dog varies in the feed amount while the front position or rear position is constant.