We report the detection of correlated anisotropies in the Cosmic Far-Infrared Background at 160 \mu m. We measure the power spectrum in the Spitzer /SWIRE Lockman Hole field .
It reveals unambiguously a strong excess above cirrus and Poisson contributions , at spatial scales between 5 and 30 arcminutes , interpreted as the signature of infrared galaxy clustering .
Using our model of infrared galaxy evolution we derive a linear bias b = 1.74 \pm 0.16 .
It is a factor 2 higher than the bias measured for the local IRAS galaxies .
Our model indicates that galaxies dominating the 160 \mu m correlated anisotropies are at z \sim 1 .
This implies that infrared galaxies at high redshifts are biased tracers of mass , unlike in the local Universe .