PROBLEM TO BE SOLVED : To provide a method for treating brain tumors, as well as a medicament for treating brain tumors.SOLUTION : Provided is a medicament for treating brain tumors, the medicament characterized by the combinational administration of 4-[4-cyano-2-({[(2' R, 4S)-6-(isopropylcarbamoyl)-2, 3-dihydrospiro[chromene-4, 1' -cyclopropan]-2' -yl]carbonyl}amino)phenyl]butanoic acid or a pharmaceutically acceptable salt thereof, and an anti-PD-1 antibody. The medicament is characterized by simultaneous or separate administration.SELECTED DRAWING : Figure 1COPYRIGHT : (C)2019, JPO&INPIT