The flotation machine includes a flotation cell (1), which comprises a vertical side wall (2) and a bottom (3), and which is upwards open. An air distribution and mixing device (4) is arranged in the vicinity of the bottom for distributing air to the slurry for forming froth and mixing the slurry in the flotation cell. The air distribution and mixing device includes a rotor part (5) that comprises air distribution apertures (6). A drive shaft (7) extends vertically in the flotation cell. The rotor part (5) is attached to the lower end of the drive shaft (7). The drive shaft comprises a hollow interior (8), which constitutes a flow channel for conducting flotation air to the air distribution holes (6) of the rotor part. An electric motor (9) is arranged to rotate the drive shaft (7). The electric motor is supported by a separate supporting framework (10), which is on top of the flotation cell. The electric motor (9) is a permanent magnet motor that comprises a vertical rotor axis (11), the lower end of which is in permanent contact directly with the upper end of the drive shaft (7).