Dyeing machine for hank yarns and/or ready-made garments, comprising: - at least one dyeing apparatus provided with: - a casing enclosing at least one dye compartment; and - at least one hermetically sealed hatch, which is provided on said casing and permits access to said dye compartment; - at least one support frame, which is mounted such as to rotate within said dye compartment and is designed to rotate, by means of at least one rotation pin, around a central axis of rotation which is horizontal and passing via said rotation pin; - at least one tank (24, 26; 44, 46), containing at least one dye bath; - at least one hydraulic circuit, which is connected hydraulically to said at least one tank (24, 26; 44, 46) and to said dyeing apparatus in order to supply said at least one dye bath from said at least one tank (24, 26; 44, 46) to said dye compartment and vice versa; and - a plurality of support means (30; 32, 34) for the hank yarns and/or the ready-made garments, which means are mounted on said support frame and are accessible via said hatch, wherein both said casing and said support frame have a circular form in vertical transverse cross-section, i.e. a cross-section obtained along a plane orthogonal to said central axis of rotation, such that said casing has a cylindrical frontal wall and that said dye compartment has a cylindrical form, wherein said hatch is provided on said cylindrical frontal wall, and wherein said support means (30; 32, 34) are disposed on said support frame according to a configuration which is preferably circumferential with respect to said central axis of rotation and are placed in the vicinity of the inner surface of said cylindrical frontal wall, the dyeing machine being characterized in that said at least one hydraulic circuit comprises one or more circuits for supply of nitrogen and air, which are connected hydraulically to said at least one tank (24, 26) and to said at least one dye compartment, such as to supply nitrogen into said at least one tank (24, 26) and said at least one dye compartment. - at least one dyeing apparatus provided with: - a casing enclosing at least one dye compartment; and - at least one hermetically sealed hatch, which is provided on said casing and permits access to said dye compartment; - a casing enclosing at least one dye compartment; and - at least one hermetically sealed hatch, which is provided on said casing and permits access to said dye compartment; - at least one support frame, which is mounted such as to rotate within said dye compartment and is designed to rotate, by means of at least one rotation pin, around a central axis of rotation which is horizontal and passing via said rotation pin; - at least one tank (24, 26; 44, 46), containing at least one dye bath; - at least one hydraulic circuit, which is connected hydraulically to said at least one tank (24, 26; 44, 46) and to said dyeing apparatus in order to supply said at least one dye bath from said at least one tank (24, 26; 44, 46) to said dye compartment and vice versa; and - a plurality of support means (30; 32, 34) for the hank yarns and/or the ready-made garments, which means are mounted on said support frame and are accessible via said hatch,