A nebulizer kit for introducing compressed air through its atomization portion to generate aerosol, comprising: an external air introduction tube (134,134d) defining an external air introduction path introducing external air; said atomization portion provided at a center position of said external air introduction tube (134,134d), said atomization portion being a compressed air nozzle tip; and a case body (110A,110D) surrounding said external air introduction tube (134,134d) and defining an aerosol carrier path communicating with an aerosol discharge port, wherein, an aerosol stream changing region of the case body (110A,110D) is provided for changing toward said aerosol discharge port a stream of the aerosol flowing in a direction away from said aerosol discharge port, the aerosol discharge port and the aerosol stream changing region being located at opposite first and second sides, respectively, of the case body (110A, 110D) with respect to the atomization portion, characterized in that said case body (110A,110D) has a first wall surface at said first side of said case body (110A, 110D) provided with the aerosol discharge port, said first wall surface being semicircular, and a second wall surface at said second side of said case body, said second wall surface being provided with a flat surface to serve as a barrier so that a stream of aerosol that flows in a direction away from the aerosol discharge port can be changed positively toward aerosol discharge part, wherein said second wall surface configures said aerosol stream changing region, a second distance from said aerosol stream changing region to said atomization portion being smaller than a first distance from said first wall surface to said atomization portion. an external air introduction tube (134,134d) defining an external air introduction path introducing external air; said atomization portion provided at a center position of said external air introduction tube (134,134d), said atomization portion being a compressed air nozzle tip; and a case body (110A,110D) surrounding said external air introduction tube (134,134d) and defining an aerosol carrier path communicating with an aerosol discharge port, wherein, an aerosol stream changing region of the case body (110A,110D) is provided for changing toward said aerosol discharge port a stream of the aerosol flowing in a direction away from said aerosol discharge port, the aerosol discharge port and the aerosol stream changing region being located at opposite first and second sides, respectively, of the case body (110A, 110D) with respect to the atomization portion, characterized in that said case body (110A,110D) has a first wall surface at said first side of said case body (110A, 110D) provided with the aerosol discharge port, said first wall surface being semicircular, and a second wall surface at said second side of said case body, said second wall surface being provided with a flat surface to serve as a barrier so that a stream of aerosol that flows in a direction away from the aerosol discharge port can be changed positively toward aerosol discharge part, wherein said second wall surface configures said aerosol stream changing region, a second distance from said aerosol stream changing region to said atomization portion being smaller than a first distance from said first wall surface to said atomization portion.