High speed electronic lockstitch buttonhole machine. This machine is equipped with built-in bobbin winder, upper and lower thread trimmer mechanism and is suitable to produce perfect straight buttonholes on a wide variety of materials. The machine is equipped with a multiple knife-dropping function. Thanks to this function, it is no longer necessary, to change the knife every time the buttonhole size is changed. The number of knife dropping times is automatically set according to the buttonhole size, in cases where the buttonhole size is frequently changed for small-lot productions or during the cycle sewing of buttonholes that are different in size. Standard maximum cutting length is 25,4 mm and standard sewing width 4 mm. Other sizes are possible with extra optional parts.