A compressor included in a fuel cell system comprises a compression chamber configured to compress the air by a rotating body; and a drive chamber arranged to separate from the compression chamber, provided with a driving mechanism that is placed therein to drive the rotating body, configured such that oil flows through, and placed to communicate with a first end portion of a depressurization pipe. When being viewed in a direction opposed to one side face of a fuel cell, a cooling medium piping and the depressurization pipe including a rising portion that is extended vertically upward are arranged to intersect with each other on the one side face.