The present invention provides gene expression regulatory DNA having activity of promoting gene expression in a mature-leaf-specific manner. The following is provided: gene expression regulatory DNA having activity of promoting gene expression in a mature-leaf-specific manner, which comprises any one of the following (a) to (d): (a) DNA consisting of the nucleotide sequence shown in SEQ ID NO: 1 (b) DNA consisting of a nucleotide sequence that has a deletion, a substitution, an addition, or an insertion of one or a plurality of nucleotides in the nucleotide sequence shown in SEQ ID NO: 1 and having activity of promoting gene expression in a mature-leaf-specific manner (c) DNA consisting of a nucleotide sequence having 90% or more sequence identity to the nucleotide sequence shown in SEQ ID NO: 1 and having activity of promoting gene expression in a mature-leaf-specific manner and (d) DNA hybridizing under stringent conditions to DNA consisting of a sequence complementary to a part or the entirety of the nucleotide sequence shown in SEQ ID NO: 1 and having activity of promoting gene expression in a mature-leaf-specific manner.
