The invention relates to a module for an air handling unit, comprising at least one side surface formed by the assembly of several panels arranged next to one another, a connection post (12) between two adjacent panels, including two facing fins (122) for positioning the panels, and two bases (14) for attaching the post (12) to an upper surface and to a lower surface (2), respectively, of the module, these bases being mounted at the two ends of the post. Each base (14) comprises two facing strips (18) which carry, on the interior side of the module, a rectilinear sealing gasket (20) for sealing the space between the fins (122) of the post (12) and the upper surface or lower surface (2) of the module.