An information recording medium is at least composed of a substrate having
a microscopic pattern constituted by a continuous substrate of grooves
formed with a groove portion and a land portion alternately, a recording
layer formed on the microscopic pattern for recording information, and a
light transmitting layer formed on the recording layer. The microscopic
pattern is formed with satisfying a relation of P.ltoreq..lamda./NA,
wherein P is a pitch of the land portion or the groove portion, .lamda.
is a wavelength of reproducing light for reproducing the recording layer,
and NA is a numerical aperture of an objective lens. The land portion is
formed with wobbling so as to be parallel with each other for both
sidewalls of the land portion. An auxiliary information based on data
used supplementally when recording the information and a reference clock
based on a clock used for controlling a recording speed when recording
the information is recorded alternately. Information is recorded in the
recording layer corresponding to only a land portion by at least either
one change of reflectivity difference and refractive index difference in
the recording layer so as to be more than 5% for reflectivity and so as
to be more than 0.4 for modulated amplitude of signal recording.