In a rewritable compact disc having a wobble groove on a substrate,
crystal and amorphous states of a phase-change recording layer are an
unrecorded/erased state and a recorded state, respectively. When the
recording layer is exposed to recording light, amorphous marks assuming
the recorded state are formed. At any of 2-, 4- and 8-times velocities
with respect to a reference velocity (1-times velocity) whose linear
velocity is 1.2-1.4 m/s, modulation m.sub.11 of a recorded signal when
the recording light of approximately 780 nm in wavelength irradiates the
recording layer via an optical system with NA=0.5 or 0.55 is 60-80%. A
topmost level R.sub.top of reflectivity of the eye pattern of the
recorded signal during retrieving at the 1-times velocity is 15-25%, and
a jitter of the individual length of marks and inter-mark spaces during
retrieving at 1-times velocity is 35 ns or less. Recording at 8-times or
higher velocities is thereby realized without any risk of impairing the
read-compatibility with the conventional CD-RW specifications at least at
4-times velocity.