A compact Raman cell based on the hollow optical fiber for highly sensitive breath analysis is reported. A polycarbonate tube-based hollow optical fiber with inner coating of silver is used for both a gas cell and a Stokes collector. An excitation laser light at 532 nm is launched into the cell filled with analytes and the Stokes light collected in the cell is detected by the multichannel Raman spectrometer. A high-reflectivity mirror was placed at the output end of the cell for the effective excitation of trace gases. The Raman spectrum of major breath molecule (oxygen, carbon dioxide, and water) is obtained without a serious decrease of the signal-to-noise ratio even if the cell is coiled into a multiple loop with a 3.8 cm radius. Because the cell examined in this report needs very small volume of only 0.4 ml or less, it has great potential for gas analyses that need fast response such as in critical care and operating rooms.