The latent image speck in AgBr emulsion grain was detected by the measurements of the photoelectric effects: the microwave photoconductivity and the photovoltage due to the Dember effect. The microwave photoconductivity of the grains exposed to saturation region on D -log H curve decreased to less than one-tenth of the value of unexposed grains. The decrease of Dember photovoltage, however, was about one half. These results can be explained on the assumption that the latent image speck acts as the deep electron trap and that its function is recovered through the combination with the interstitial silver ion.