thread take up 11 has a corresponding needle bar 9 a thread tension frame 12 made of synthetic resin and which is slightly inclined in the upper rear direction is fixed on the upper end of the needle bar case 7 six thread tension regulators 13 are provided on the thread tension frame 12 each thread tension regulator 13 is associated with needle thread t used by each sewing needle 10 six spool pin bases 14 are provided on the upper side of the arm 3 thread spools 15 serving as thread supply are attached on such spool pin bases 14 the needle thread t drawn from each thread spool 15 is hooked on the corresponding thread tension regulator 13 thread take up 11 and the like and supplied to the sewing needle 10 a needle bar switching mechanism not shown having a needle bar switching motor 32 refer to fig2 is provided inside the arm 3 the needle bar case 7 is moved in the lateral direction integrally with the thread tension frame 12 by the needle bar switching mechanism thus one of the six needle bars 9 and the thread take ups 11 are selectively switched to the active position when the sewing machine motor 31.