<p>Disclosed is a therapeutic and/or prophylactic agent for cancer pain, which can be administered continuously for a long period between the early stage and the final stage of the cancer pain therapy in place of conventional non-opioid or opioid analgesic agents. The therapeutic and/or prophylactic agent for cancer pain comprises a 1,5-benzodiazepine derivative represented by general formula (1) [wherein R1 represents a C1-6 alkyl group; R2 represents a phenyl group or a cyclohexyl group; and Y represents a single bond or a C1-4 alkylene group] or a pharmaceutically acceptable salt thereof as an active ingredient.</p>
