With the purpose of the analytical study of the left-right differences ire the tachistoscopic recognition, four experiments were conducted, in the monocular visual field, in the situation where subjects feel as if the experiments were conducted on there. with binocular viewing. Both experiments under the traditional successive and simultaneous conditions showed, in the Japanese words, better recognition in the right visual field. In the single letter and non-letter materials, significant difference was not seen. Concerning the verbal reaction time for the word material, which were presented tachistoscopically in the right or in the left of the fixation point, both, eyes showed a slightly faster tendency in the right visual field. In the immediate memory experiment, in which the similar procedure to the one used in dichotic listening was employed, higher scores were shown in the temporal visual field. In the four experiments, only the left eye showed significant differences between the visual fields. Three factors were discussed-attentional processes, superior sensitivity of the nasal retina and eye dominance.