An information recording medium (10) including a first region (11) in which medium identification information has been recorded, a data region (13), and a second region (12) which is positioned between the first region (11) and the data region (13) and in which control information has been recorded, in which an area of the first region (11) is greater than an area of the second region (12) in size.

An information recording medium (10) including a first region (11) in which medium identification information has been recorded, a data region (13), and a second region (12) which is positioned between the first region (11) and the data region (13) and in which control information has been recorded, in which an area of the first region (11) is greater than an area of the second region (12) in size.

An information recording medium (10) including a first region (11) in which medium identification information has been recorded, a data region (13), and a second region (12) which is positioned between the first region (11) and the data region (13) and in which control information has been recorded, in which an area of the first region (11) is greater than an area of the second region (12) in size.

An information recording medium (10) including a first region (11) in which medium identification information has been recorded, a data region (13), and a second region (12) which is positioned between the first region (11) and the data region (13) and in which control information has been recorded, in which an area of the first region (11) is greater than an area of the second region (12) in size.

An optical disk (100) of the present invention includes (i) a medium information region (101) (a) in which type identification information is recorded by recesses and/or protrusions which are formed by a given modulation method and whose lengths are longer than a length of an optical system resolution limit of a playback device and (b) in which first address information is recorded in a first address data format and (ii) a data region (102) (a) in which content data is recorded by recesses and/or protrusions which are formed by the given modulation method and which include a recess and/or a protrusion whose length is shorter than the length of the optical system resolution limit and (b) in which second address information is recorded in a second address data format.

An optical disk (100) of the present invention includes (i) a medium information region (101) (a) in which type identification information is recorded by recesses and/or protrusions which are formed by a given modulation method and whose lengths are longer than a length of an optical system resolution limit of a playback device and (b) in which first address information is recorded in a first address data format and (ii) a data region (102) (a) in which content data is recorded by recesses and/or protrusions which are formed by the given modulation method and which include a recess and/or a protrusion whose length is shorter than the length of the optical system resolution limit and (b) in which second address information is recorded in a second address data format.

An information recording medium (10) including a first region (11) in which medium identification information has been recorded, a data region (13), and a second region (12) which is positioned between the first region (11) and the data region (13) and in which control information has been recorded, in which an area of the first region (11) is greater than an area of the second region (12) in size.

An information recording medium (10) including a first region (11) in which medium identification information has been recorded, a data region (13), and a second region (12) which is positioned between the first region (11) and the data region (13) and in which control information has been recorded, in which an area of the first region (11) is greater than an area of the second region (12) in size.

In a case where (i) a reflectance calculated from a reflected light amount obtained from a longest pit (P1max) or a longest space (S1max) in a first pit row is defined as a first reflectance and (ii) a reflectance calculated from a reflected light amount obtained from a longest pit (P2max) or a longest space (S2max) in the second pit row is defined as a second reflectance, the first pit row is formed such that the first reflectance becomes substantially identical with the second reflectance.

In a case where (i) a reflectance calculated from a reflected light amount obtained from a longest pit (P1max) or a longest space (S1max) in a first pit row is defined as a first reflectance and (ii) a reflectance calculated from a reflected light amount obtained from a longest pit (P2max) or a longest space (S2max) in the second pit row is defined as a second reflectance, the first pit row is formed such that the first reflectance becomes substantially identical with the second reflectance.