The present invention provides a volume type compressor, which miniaturizes the oil returning mechanism of the volume type compressor. The volume type compressor has an oil returning mechanism which separates the oil, which is injected from an oil storage unit (125) storing the oil to a compression chamber (100) for compressing the working fluid, from the compressed working fluid, and then returnsthe oil back to the oil storage unit. The oil returning mechanism has an oil return chamber (95) for temporary accumulation of separated oil from the oil separation mechanism, and a float valve body(70ab) which is composed of a hollow float (70a) and a float valve part (70b) and floats on the stranded oil accumulated at the bottom of the oil return chamber, wherien the float valve body is used to open and closed a float hole (70c) connected to an oil return pipe (80) communicating the oil return chamber and the oil storage unit, and the hollow float forms a float pressure-sharing pipe communicating the work fliud regions of the hollow uint and the oil return chamber, thus it is no need to consider a pressurization design for avoiding the pressure differernce between the work fliud regions of the hollow uint and the oil return chamber, so that a small hollow float could be constituted.