The present invention addresses the problem of providing an antiviral agent, in particular, an anti-HIV agent having a novel function mechanism. Provided is a drug that is an antiviral agent comprising a compound represented by general formula (I) or a pharmaceutically acceptable salt thereof as an active ingredient, said drug having a proliferation inhibiting effect, cell membrane fluidity-decreasing effect, cell membrane fusion-inhibiting effect, etc. on HIV. In general formula (I), each symbol is as defined in the description.
