The invention addresses the problem of providing an endoplasmic reticulum stress regulator and a method for regulating endoplasmic reticulum stress. A polynucleotide that regulates the levels or functions of miR-193b, miR-423, miR-15b, miR-20b, and miR-92a, miR-199a*, miR-23a, miR-27a, miR-29b, miR-181b, miR-196a, miR-221, miR-26a, miR-27b, miR-143, and miR-24-2.