The present invention relates to a scroll compressor. The scroll compressor is configured to have bypass holes communicated with compression chambers so as to bypass a part of a compressed refrigerant and thus to modulate a capacity of the compressor, a middle pressure chamber and a valve. Accordingly, it is capable of simplifying a capacity modulation apparatus of the scroll compressor, thereby miniaturizing the compressor and reducing a fabrication cost. And, as the bypass holes are disposed to be adjacent to each other, an operating capacity of the compressor can be easily modulated with only one bypass valve, accordingly it is capable of reducing the number of bypass valve and of enhancing reliability.