An information recording medium having at least a read only area and a recording
and reproducing area is composed of at least: a substrate; a recording layer formed
on the substrate so as to record and reproduce information; and a light transmission
layer having transparency formed on the recording layer. The information recording
medium is further characterized in that a wobbling groove corresponding to the
read only area and another wobbling groove corresponding to the recording and reproducing
area is formed on the substrate without overlapping with each other, the recording
and light transmitting layers are continuously adhered over at least two areas
of the read only area and the recording and reproducing area, reflectivity of the
recording layer is more than 5%, and a push-pull signal output T3 reproduced
from the read only area and another push-pull signal output T4 reproduced
from the recording and reproducing area before recording satisfies relations of
T30.1, T40.1 and 1.5T3/T40.5.