There is provided a machining control system which is capable of keeping the optimum machining states and enhancing the efficiency and the reliability even in the case where an actual machining environment fluctuates. A machining control system includes a machining information determination portion (102) for determining initial machining conditions (107) on the basis of information (105) stored in a machining data base (101) and in accordance with adaptive control characteristics (106) defined by adaptive control modes and adaptive control parameters, and an adaptive control portion (103) for controlling the machining in appropriate states by changing the machining conditions in accordance with the machining states observed during the machining with the initial machining conditions (107) as an initial value of the machining conditions.