To provide an elastic yarn which can be used as a raw yarn for preventing the slip (slip-down) of a knitted or woven fabric (socks, supporter, trousers, or the like).

This elastic yarn as a raw yarn for preventing the slip of the knitted or woven fabric is characterized by fusing an elastomer or synthetic resin having a large frictional resistance on the surface of one of various core fiber. The elastic yarn as a raw yarn for preventing the slip of the knitted or woven fabric is characterized by comprising a covered yarn prepared by loosely winding a slightly stretched or non-stretched rubber yarn or the like with a covering yarn. The elastic yarn as a raw yarn for preventing the slip of the knitted or woven fabric is characterized by comprising a covered yarn 401a prepared by winding a slightly stretched or non-stretched rubber yarn 404a or the like with a covering yarn 405 so that the elastic yarn is knitted or woven and then melted in hot water or a hot chemical liquid. The elastic yarn as a raw yarn for preventing the slip of the knitted or woven fabric is characterized by comprising a covered yarn prepared by winding the surface of a core yarn with an elastic yarn.