The present disclosure relates to a window
assembly having a ventilation function and a horizontal close-fitting function, and more particularly to a horizontal close-fitting window
assembly for implementing crime prevention and security functions by preventing a window from being open even in a ventilated state with the outside in which the window is slightly open and conveniently opening the window. The window
assembly having a ventilation function and a horizontal close-fitting function includes a window sash, a window frame in which the window sash is installed to slide, a
handle rotatably installed on the window sash, a latch provided on a side surface of the window sash and operatively connected to movement of the
handle to move in up and down directions, a latching guide that is provided on the window frame at a relative position facing the latch and by which the latch is or is not latched depending on a position of the latch, and a horizontal movement device provided on at least one of a top surface or a bottom surface of the window sash and operatively connected to the
handle to cause horizontal close-fitting or horizontal close-fitting release of the window sash depending on movement of the handle, wherein the latching guide includes a first latching region positioned at an upper part, a second latching region located lower than the first latching region while being spaced apart from the first latching region, and a separation space provided between the first latching region and the second latching region, and a vertical
central line of the first latching region and a vertical
central line of the second latching region are displaced from each other, and when the latch is located in the first latching region or the second latching region, horizontal close-fitting or horizontal close-fitting release of the window frame is inducted, and when the latch is located in the separation space, the window sash is slidably moveable with respect to the window frame.