An optogalvanic spectroscopy method for study of atomic mercury metastable level is reported. The experiments are described in which the mercury discharge was irradiated with a dye laser at 577 nm and 579 nm, thus exciting the atoms from the 61P1 level to 63D level, which decays to the 63P levels. By measuring the time dependence of the optogalvanic and fluore-sence signals, the effective lifetime and the ambipolar diffusion coefficients were obtained. The theoretical explanation for the experiments is presented.