A rotary-type fluid machine (10A) includes: a closed casing (1) having a bottom portion utilized as an oil reservoir, a rotary-type fluid mechanism (expansion mechanism) (15) that is provided in an upper portion of the closed casing (1) and in which working chambers (32, 33) in cylinders (22, 24) are partitioned into a suction side working chamber and a discharge side working chamber by vanes (28, 29), a shaft (5) having therein an oil supply passage (51) for supplying oil to the fluid mechanism (15), the shaft being connected to the fluid mechanism (15) and extending an oil reservoir (45), an oil pump (52) provided at a lower portion of the shaft (5), an oil retaining portion (65) for retaining oil, which is pumped up by the oil pump (52) and supplied through the oil supply passage (51), in a surrounding region around the fluid mechanism (15) to allow the partitioning members of the fluid mechanism (15) to be lubricated, the oil retaining portion formed so that the liquid level of the oil retained therein is positioned higher the lower face of the partitioning members (28, 29).