Metallic pyrochlore oxide Cd₂Re₂O₇, the first superconductor in pyrochlore oxide family, shows a structural phase transition from cubic to tetragonal at Tc = 200 K. However, while the transport properties exhibit dramatic change across Tc, the lattice parameter change is extremely small and the electron correlation is argued as a driving force of the phase transition. Recently a multipolar nematic phase has been observed by second harmonic generation, proving this theory. Despite the interest in this material, no experimental Fermiology has been reported so far. We report the first observation of de Haas van Alphen quantum oscillations in single crystals of Cd₂Re₂O₇ by torque magnetometry. The angular dependence of oscillation patterns and its comparison to the theoretical prediction will be discussed.