<p>Microgravity environment has been used to obtain high-quality crystals. Strong magnetic force produced by a superconducting magnet can cancel out the gravity force, enabling construction of quasi-microgravity environment on earth. We developed a protein crystallization system which is composed of a superconducting magnet for the magnetic force-based quasi-microgravity and an inverted periscope for in situ observation of crystal growth. Crystals grown in the system showed improved and homogeneous quality.</p>