It is shown that the cosmological constant problem inbrane-world is different from the same problem in generalrelativity, essentially because the gauge fields fields contributingto the vacuum energy are confined to the brane-world, but the cosmological term propagates in the bulk. The brane-wrld equations of motioninclude a second order, conserved symmetric tensor field infour dimensions defined by the extrinsic curvature, whichadjusts the vacuum energy. In the application to theFRW brane-world universe embedded in a five-dimensional deSitterbulk, that tensor modifies Friedman's equation with a remarkable agreement with the current gold set of cosmological data.