Disclosed is an optical fiber pressure sensor including: a polarization beam splitter that splits input light from a broadband light source into two beams; a polarization controller through which vertically and horizontally polarized light coming out of the polarization beam splitter pass; a pressure chamber in which the polarization beam splitter and the polarization controller may be placed; and an optical spectrum analyzer into which vertically and horizontally polarized light passing through the polarization controller and getting out of the polarization beam splitter is introduced, wherein the pressure chamber includes a polarization-maintaining fiber and an optical fiber Bragg grating.