A large capacity recording medium is formed by bonding at least two disc-shaped recording plates to provide a structure adapted to absorb any manufacturing errors in the direction of the height of the recording medium. The second substrate (3) has a projecting section (23) entering a plate receiving recess (11) of the first substrate (2) keeping a gap (C1) between the front of it and the plate receiving recess (11). A raised section (6) of the first substrate (2) may be exposed through an exposure in a cartridge.