Abstract: A suturing instrument for a surgical operation includes a suturing portion having a base, a vertically reciprocating needle holder carrying a needle with an upper thread, a device for supplying a predetermined amount of the upper thread to the needle and a loop taker supported in the base for turnable movement relative thereto and operative for catching a thread loop formed on the needle. The device for supplying the upper thread, the loop taker and the needle holder are activated for sequential operation by a control portion of the instrument which includes a fluid drive device connected to the suturing portion and including a plurality of hydraulic cylinders. The control portion is activated by a manually operated switch which actuates an electric circuit and a switching device operating a plurality of the cylinders for sequentially imparting the reciprocating movements to the needle, the loop taker and the thread supplying device.