A novel immunostimulatory oligonucleotide by which anIFN-inducing activity is enhanced and an inflammatorycytokine-inducing activity is reduced, and a pharmaceuticalcontaining the same, and an aplication thereof are provided.That is, the present invention provides theimmunostimulatory oligonucleotide composed of a basesequence represented by a formula: 5'-(G)MPXCGYQ(G)N-3' (Xand Y are mutually independent and represent an arbitrarysequence which has a length of 0 to 10 nucleotides and doesnot contain 4 or more consecutive G residues, and a lengthof X + Y is 6 to 20 nucleotides； XCGY contains a palindromesequence having a length of at least 8 nucleotides and hasa length of 8 to 22 nucleotides； P and Q are mutuallyindependent and represent one nucleotide other than G； Mrepresents an integer of 6 to 10 and N represents aninteger of 0 to 3) wherein a full length thereof is 16 to37 nucleotides (except for an oligonucleotide composed of abasesequence represented by SEQ ID NO:5), thepharmaceutical application thereof.
