A chlorine dioxide gas generating agent pack includes a chlorine dioxide gas generating agent containing a mixture of chlorite powder, gas generation control agent powder, moisture-absorbent powder, water-absorbent resin powder, and activating agent powder and a gas-permeable film container permeable to water vapor and chlorine dioxide gas and containing the chlorine dioxide gas generating agent. This chlorine dioxide gas generating agent pack is suitable for being carried to a region where sterilization, disinfection and deodorization are required.