The present invention relates to a surgical tool guide, which is easily installed and separated to reduce operating time, and furthermore surgical instruments are not separated from the abdominal walls or gas does not leak to stably perform the surgical operation. In addition, the present invention relates to a protection cap for a surgical instrument guide, which is interlocked together with surgical instruments to maintain a seal even though the surgical instruments for the operation are variously moved, thereby efficiently preventing the leakage of gas. Therefore, since it is unnecessary to inject gas again during the operation, the surgical operation can be smoothly performed.