An apparatus for treating cardiovascular diseases includes an expandable support member having oppositely disposed proximal and distal end portions and a main body portion between the end portions for positioning in a blood vessel. The compressor compresses refrigerant gas and changes the displacement. The component electrode is laid above the solder resist so as to form a clearance communicating with the outside of the component electrode, so that gas generated by vaporization of a flux component contained in the solder during reflow-heating is passed through the clearances and let out of the component electrode.