To assess whether the information processing dysfunction in schizophrenics occurs at preattentional level or attentional level, the authors investigated information processing in schizophrenia with 40 schzophrenics diagnosed by DSM-III-R and 40 normal males. The basic methodology relied on Treisman’ s feature-integration theory and the visual search task. Slopes and intercepts of response time which were obtained by linear regression, and response times between two groups were analysed by M ANOVA and the results were obtained as follows. 1) The slopes of response times of the schizophrenics exceed those of controls and the slopes of schziophrenics in conjunction condition exceed the slopes of schizophrenics in feature condition. The above results suggest that information processing dysfunction in chronic schizophrenics occurs at both preattentional level and attentional level but more at attentional level. 2) Intercepts of response times of the schizophrenics exceed those of controls, which suggest that schizophrenics were also impired at the early stage of informational processing. The above results suggest that information processing dysfunction in chronic schziophrenics occurs both at preattentional level and attentional level but more at attentional level.