We demonstrate a new way of operating an optically pumped magnetometer with miniaturized cesium cell using the light-narrowing effect. The magnetometer setup shows improvement of shot-noise limited sensitivity (42fT/sqrt(Hz) in a cell of only 9.3mm^3 volume) due to the suppression of spin-exchange relaxation to a large extent and the use of a strikingly increased fraction of alkali atoms for signal generation, working even in µT magnetic fields, by using only one single high-intensity laser beam both for pumping and probing of atomic spins.