PROBLEM TO BE SOLVED: To provide means to treat anticancer agent-resistant cancer.SOLUTION: The present invention provides 1-(2,3-dihydroxy-1-hydroxymethyl propyloxymethyl)-2-nitroimidazole represented by the following structural formula. The present invention also provides an ABC transporter inhibitor that is used for the treatment of anticancer agent-resistant cancer under a low oxygen condition.SELECTED DRAWING: None