Disclosed herein is a cell death-inducing peptide that rapidly acts. The peptide is derived from Noxa protein and comprises 16 amino acid residues including MTD. The peptide is designated extended MTD (eMTD) because it contains the 10-mer MTD. eMTD rapidly exhibits potent necrotic cell death in various cell lines and, as such, can be applied to the treatment of various diseases including cancer when used in conjugation with peptides or materials for targeting specific cells.