The invention discloses an ammonia concentration increasing device. The ammonia concentration increasing device mainly comprises at least one first shell-and-tube type heat exchanger, a terminal shell-and-tube type heat exchanger and a heat energy supply device, wherein the terminal shell-and-tube type heat exchanger is connected with the heat energy supply device and the first shell-and-tube type heat exchanger, and the heat energy supply device is used for heating ammonia water in the terminal shell-and-tube type heat exchanger, so that ammonia gas and hot ammonia water are formed. The produced ammonia gas and hot ammonia water are delivered to the first shell-and-tube type heat exchanger by the terminal shell-and-tube type heat exchanger, and ammonia water in the first shell-and-tube type heat exchanger is heated. According to the ammonia concentration increasing device, ammonia water can be converted into high-concentration ammonia gas effectively, and energy consumption in a conversion process can be reduced.