PURPOSE: To prevent the retention of fluid in which the supply or exhaust of the fluid is instantaneously reduced at the time of switching a channel in a simple switching structure which can switch the flow of high-temperature fluid between at least two system channels and the leakage or mixture of gas is small.

CONSTITUTION: The second and first fluid chambers 6a, 6b of exit and entrance means 6 communicate with three or more chambers 9a, 9b, 9c of partition means 2 via second and first fluid communicating holes 5, 4 of switching means 3, first and second fluids flow to any of the chambers 9a, 9b, 9c in the means 2 without crossing with the first and second fluids to switch the flowing direction. Further, the means 3 for controlling the flows of the first and second fluids is formed of ceramic matrix composition having thermal conduction coefficient at a high temperature and excellent heat resistant shock coefficient, and even if the fluid of a high temperature such as the temperature higher than 400°C flows, the stable operation for a long period can be ensured.