Considering the human cerebral-hemispheric specialization, specific tasks can be performed under a certain sound environment without any interference effects. Under other conditions, strong interference effects occur between the task performance and the sound environment [Y. Ando, Acustica 64, 110--116 (1987)]. For example, the left hemispheric tasks can be interrupted by the verbal sound, and the right hemispheric tasks can be interrupted by nonverbal sounds like noise. In order to identify hemispheric specialization for some important tasks, which are often performed in an office, the effective durations of the autocorrelation function of the (alpha)-brain wave range from both left and right hemispheres are analyzed here. Results may be utilized to design the recommended sound environment for each task in the office.