Novel ventilation device for building

The invention discloses a novel ventilation device for a building. According to the novel ventilation device, the small end of the upper part of a lower conical pipe and the small end of the lower part of an upper conical pipe are close to and connected with each other, and a connecting sucker is connected between the lower conical pipe and the upper conical pipe, therefore, after airflow in the lower conical pipe flows to the upper conical pipe, a certain negative pressure is formed at the connecting sucker due to the contraction and diffusion effects of the conical pipes, and the negative pressure can make a suction pipe suck the airflow; and meanwhile, an airflow control mechanism can make the flow velocity of the airflow flowing from the lower conical pipe to the upper conical pipe continuously change periodically or aperiodically, and can effectively make the sucked airflow in the suction pipe change as well, so that the airflow change of the airflow during the humidity adjustmentis facilitated, it is en