Dynamically Reconfigurable Processors improve the area-efficiency by executing a task with multiple hardware contexts. The maximum operational frequency is limited with a context which has the largest delay time, and it causes a certain overhead when each context has various delay time. A context dependent dynamic clock control method, which changes the clock so as to fit the current operational context, is proposed for NEC electronics' DRP-1. A clock generator consisting of a preset-able counter associated with the state transition table for controlling the context switching is proposed. Performance evaluation using several applications reveals that the proposed method improves the performance from 10% to 110% with a small increasing of the power consumption.