Thanks to all of you for viewing! It has been 4 years since I potted it with coarse-grained granite and bark grains in this plastic pot. I noticed that its root grows into the neighbor pot full of broken piece of tile. That shows it like it.
I agree that roots of Angreacum don't like being disturbed. I had ever heard that a largest one here owned by an orchid farm died after repotting.
I plant them together with Dendorbium and Cattleya. Water it after it is completly dry. In winter control watering. It is not a difficult one,but need patience.