The present invention provides an oligonucleotide derivative that enables to easily synthesize an oligonucleotide derivative chemically modified at the 3′-end with two moieties each having a benzene or pyridine structure with a few steps, an aromatic compound serving as a precursor for preparing the modification carrier for synthesizing oligonucleotide derivative, and the oligonucleotide derivative and the oligonucleotide construct using the same, that is chemically modified at the 3′-end with two moieties each having a benzene or pyridine structure, and has good permeability through a cell membrane and excellent nuclease resistance. The modification carrier for synthesizing oligonucleotide derivative, comprising a unit and a carrier carrying the unit directly or via a linker, wherein the unit is represented by the formula (a): wherein, R1 to R6 each independently represent hydrogen or a substituent other than hydrogen; Z1 and Z2 each independently represent CH or nitrogen; and X represents oxygen or sulfur.