The Fermi surface (FS) of the organic superconductors, κ'-type and κ'-type (BEDT-TTF) ₂Cu₂ (CN) ₃ was investigated through the angle-dependent magnetoresistance oscillation (AMRO) and Shubnikov-de Haas (SdH) oscillation under pressure using a clamp cell which can be rotated in a cryostat. The AMRO signals were more prominent in the κ-type salt than in the κ'-type salt. The topology and the pressure dependence of the observed FS's are similar with each other, being consistent with the calculated FS. However, the FS with a small cross-sectional area obtained by the SdH measurement exhibits stronger pressure dependence.