The invention provides a placement ventilation device comprising an air intake unit, an air outtake unit and a control unit. An air intake of the air intake unit is arranged inside a corner of a walland projects a wall to form a circular sector structure; a sector flow velocity controller is arranged inside the air intake unit, the flow velocity is controlled according to the ground length corresponding to angles of each point of an air outtake so as to ventilate for a certain time; the coverage air intake quantity of each point on a horizontal position of the air intake is substantially consistent, and structures of the air outtake unit can be different as required. A circular sector air intake is arranged in the placement ventilation device, the air intake velocity can be designed according to a house structure so as to ventilate for a certain time, the coverage air intake quantity of each point on the horizontal position of the air intake is substantially consistent, therefore, theinvention has the obvious effect that the whole ventilation system is closer to an ideal state of the placement ventilation.