An experimental apparatus was designed to investigate the crystal morphology and growth rate of naphthalene crystals grown in various processes using supercritical carbon dioxide, including SCG (single crystal growth), SESS (slow expansion of supercritical solution), and RESS (rapid expansion of supercritical solution). Photographs were taken to identify crystal habits. The growth rates of naphthalene in the SCG and SESS processes were measured and compared with those in a RESS process.