A data block read-out control apparatus includes: an order buffer that stores an identifier sequence in which sort-unit identifiers corresponding to data blocks stored in reception buffers prepared for each sort unit are arranged in arrival order of the data blocks; a detecting unit that detects a head position of the sort-unit identifiers in the identifier sequence; a determining unit that determines a data block to be read out from one of the reception buffers, based on at least the head position of the sort-unit identifiers and a read-out rule of data blocks from the reception buffers defined in advance; and a reading-out unit that reads out the data block determined in the determining unit, from the one of the reception buffers, wherein the sort-unit identifiers are expressed by a minimum bit number to express all sort units corresponding to the data blocks stored in the reception buffers.