21 and flanges 22 b 22 b of lower part 22 hold coil winding portions 14 a 14 b in an axial direction and firmly fix weight 20 fixed between selected core winding portions 14 a 14 b under the present embodiment when coils 15 a 15 b and 15 c of respective rotors 3 are energized by slip spring 16 rotors 3 are driven about rotary shaft 11 since weight 20 is inserted and fixed between selected coil winding portions here shown as winding portions 14 a and 14 b a center of gravity of the plurality of rotors 12 is deviated eccentrically from a center of rotary shaft 11 consequently when rotors 12 are driven vibration generating motor 10 as a whole generates vibration according to another beneficial aspect of the present invention weight 20 is inserted and simply and quickly fixed by use of securing or coupling means such as rivet 23 between coil winding portions 14 a and 14 b of each core 14 thus welding work is not necessary and production costs and time for motor 10 can be reduced additionally since it is easy to remove upper and lower parts 21 22 of weight 20 by quickly removing rivet 23 it is possible to rapidly recycle used weights thereby saving time money and reducing material waste additionally referring now to fig6 and 7 a second embodiment of the present invention includes an alternatively designed weight 30 similar to the above described embedment weight 30 is inserted and fixed in a space formed between two adjacent coil winding portions shown here as winding portions 14 a and 14 b weight 30 is constructed of.