To provide an electromagnetic wave suppression flat yarn having excellent flexibility and attachable to bending parts, harnesses and electric wires without causing cracking and stiffening troubles to enable the reduction of the weight and size of electronic instruments, and a method for producing the flat yarn.

Provided are an electromagnetic wave suppression flat yarn having an electromagnetic absorbing resin layer (I) with an electromagnetic wave absorbing performance comprising a reflection loss (S11) of -1 dB over the whole electromagnetic wave frequency range of 300 MHz to 18 GHz measured in conformity to IEC-62333 and a transmission loss (S21) of -1 dB over the whole electromagnetic wave frequency range of 300 MHz to 18 GHz and a resin layer (II) on one surface of the electromagnetic wave absorbing resin layer (I) or having the resin layer (II) on one surface of the electromagnetic wave absorbing resin layer and a resin layer (III) on the other surface, and used in a woven fabric, a knitted fabric or a braid, an electromagnetic wave suppression product produced by using the flat yarn, and methods for producing the yarn and the product.