General Antiparticle Spectrometer (GAPS) is an experiment looking for antideuteron particle from outer space cosmic rays. Anti-deuterons can be a crucial signature of dark matter annihilations. GAPS uses long-duration balloon experiments looking for anti-deuteron particles. The GAPS ground test was successfully using an particle accelerator at KEK in 2004 and 2005. The first high-altitude balloon test was done in June 2012 with six Si(Li) detectors.