solenoid 23 is operated to attract operation bar 24 then the operation lever 29 rotates making the supporting shaft 28 the center of rotation and causes the end of engaging lever 49 to rise up as shown in fig4 a and fig5 a the rotation of operation lever 29 makes needle bar stopper 32 descend and the engaging part 31 is inserted into the engaging groove 12 of the needle bar 8 and the needle bar 8 is prevented from moving on the other hand inclined surface 33 at the end of the operation lever 29 causes roller 56 of the engaging lever 49 to move upwards makes engaging lever 49 rotate around the pin 50 and makes the end point face down by this downward facing of the point end the pressure surface 53 of the pressing member 52 moves off from the stopper 18 of the moving block 13 under this condition when the driving band 40 is advanced the roller 56 moves along the inclined surface 33 of the operation lever 29 and the engaging lever 49 moves so as to be maintained in an inclined condition and the engaging lever 49 is then oriented in a horizontal condition by the action of the coil spring 55 insofar as the pressing member 52 has already passed the position of the stopper 18 at the position of the roller 56 has left from the inclined surface 33 therefore only the stopping lever 49 advances.