To provide a ventilation structure in an opening part of a building which can be applied to a door of any kind which is provided at an opening part formed in a wall body irrespective of the kind, and enables mutual ventilation between spaces partitioned by the wall body.

The ventilation structure in the opening part of the building including a partition wall 21, in which an opening part opened/closed by a door 20 is formed, and a vertical frame member 25 of a door frame body provided on a partition wall inner periphery 27 of the opening part has an air passage 43 between the vertical frame member 25 and the partition wall inner periphery 27 to enable the air to mutually circulate between the spaces partitioned by the partition wall 21. Since the air passage 43 is provided between the vertical frame member 25 and the partition wall inner periphery 27, mutual ventilation between the spaces partitioned by the partition wall 21 is enabled. In addition, since the air passage 43 is provided between the vertical frame member 25 and the partition wall inner periphery 27, the ventilation structure can be applied irrespective of the kind of the door 20 which is installed, unlike the case where the air passage 43 is provided outside the vertical frame member 25.