A lignocellulosic biomass saccharification pre-treatment device for easily recovering ammonia water to be used in a pre-treatment for saccharification of a lignocellulosic biomass and recycle use. The device has a mixing unit 2 mixing lignocellulosic biomass and ammonia, a heating unit 3 heating the mixture, a separation unit 4 separating ammonia gas from the mixture to obtain a biomass-water mixture, and a transfer unit 6 transferring the biomass-water mixture to a later process. An ammonia water supply unit 8 supplies ammonia water to the mixing means 2. An ammonia recovery unit 20 recovers ammonia gas as ammonia water. A heat-of-dissolution recovery unit 24 recovers heat-of-dissolution generated when ammonia gas is dissolved in water. A heat pump unit 30 generates heat to be supplied to the heating unit 3 using at least the heat-of-dissolution as a heat source.