Information recording/reproducing apparatus and a data reproducing method thereof, as well as an optical disk thereof

A data reproducing method for reproducing data, upon an optical disk of rewritable type, having an alternated block management area, a data area, on which recording/reproducing of the information is conducted by a unit of block, and an alternation area, on which recording/reproducing of information including a defective sector therein is conducted by the unit of block, through an information recording/reproducing apparatus enabling to execute Read Modify Write operation thereon, comprising the following steps of, in case where said alternation areas are in a plural number thereof when executing Read Modify Write operation onto said optical disk of rewritable type: executing reproducing on said data area including the defective sector therein, by only one (1) time; executing reproducing on said alternation area, thereafter, so as to hold data reproduced; and thereby reproducing the data. With this, it is possible to increase speed (i.e., speedup) in the reproducing time thereof, in total, but without necessary of reproducing operation upon the data area by a plural number of times.