To solve the following problems: when pressure of a working fluid is large, it is difficult to apply a gas bearing with a small load capacity to a rotary machine because a large differential pressure occurs in a turbine moving blade or a compressor impeller and an excessive thrust force acts thereon.

In a thrust bearing structure, the pressure in a space formed between a main thrust bearing and a thrust collar is increased by means of a flow path communicating with the space and with a flow path near a moving blade inlet port or upstream of a nozzle, to increase the thrust load capacity by means of fluid pressure.