The relation between prefrontal cortex and cerebro-cerebellar functions of 50 normal healthy elderly people was examined. The function of the prefrontal cortex was measured by means of a letter fluency test and the Digit Cancellation Test (D-CAT, a test for the assessment of attention). Two indexes of postural tremor measured by the stabilometer were employed for the indication of cerebello-thalamo-cortical circuit functions. The results of groups consisting of participants showing higher or lower scores than the mean of the norm on the stabilometer index measurements were compared with their D-CAT and letter fluency test performances. The results showed that 2 indexes of cerebello-thalamo-cortical circuit functions related to the attention function while the relation to the language function was rather weak. The results of the behavioral measures demonstrated a mutual relation between prefrontal cortex and cerebello-thalamo-cortical circuit functions and strongly suggest the notion that the human brain functions as a system, which includes neocortex, subcortex, and cerebellum.