In replenishing a glue container with hot-melt glue, to enable stable supply of the glue in solid form without it clogging the resupply path from the hopper, provided are: a sheet retaining unit for retaining a sheaf in a glue application position; a glue applier in a hot-melt-glue-receiving container, disposed in the glue application position, for applying glue to an endface of a sheaf there; a heater, disposed in the glue container, for heating/melting the glue inside; a heater temperature controller; a resupply hopper above the glue container for replenishing it with solid glue; a vacuum ducting unit above the container and adjoining the resupply hopper, for suctioning up glue evaporation derivatives; and a control unit configured to run the vacuum ducting unit when the glue container is being replenished with glue, to prevent or mitigate invasion of evaporation derivatives into the resupply hopper.