true, GWs from infinite strings can give dominant contribution to the GW background at those low frequencies, as we will show in this paper. Second, infinite strings can emit GWs with wavelength of horizon scale because the characteristic scale of infinite strings is as long as the size of the horizon. This may be detected by future and on-going CMB surveys. Loops cannot emit GWs with such long wavelength. $^{2}$Thus, we are lead to consider GWs from infinite strings. A structure on infinite strings which is responsible for GW emission is a kink. $^{3}$Kinks are produced when infinite strings reconnect and kinks on the infinite strings can produce GW bursts. The kinks are sharp when they first appear, but are gradually smoothened as the Universe expands. Moreover, when an infinite string self-intercommutes and produces a loop, some kinks immigrate from the infinite string to the loop, and hence the number of kinks on the infinite string decreases. Recently, Copeland and Kibble derived the distribution function of kinks on an infinite string taking into account these effects [13]. However, they did not study the GWs from kinks. Therefore, in this paper, we investigate GWs from kinks using the kink distribution obtained in [13] and discuss the detectability of them by future GW experiments, especially by pulsar timing, such as Square Kilometer Array (SKA) and space-based detectors such as DECIGO and BBO. This paper is organized as follows. In section 2, we briefly review a part of the basis of cosmic strings. In section 3, we derive the distribution function of kinks on infinite strings according to [13]. In section 4, we derive the formula of the energy radiated from kinks per unit time. In section 5, we calculate the spectrum of stochastic GW background originating from kinks, using formula derived in section 4. Section 6 is devoted to summary and discussion. 2 Other recent simulations imply α ∼ 0 . 1, which is much bigger than Gµ . In this case loops can emit GWs whose wavelength is comparable to or somewhat shorter than the horizon scale [12]. 3 Generically, infinite strings do not have any cusp since its existence depends on the boundary condition of the string, i.e., the periodic condition. 3