Provided is a turbocompressor (4) having a drive part (12) generating rotational power, an impeller (22a) to which the rotational power of the drive part (12) is transmitted to rotate, a plurality of gears (31, 32) transmitting the rotational power of the drive part (12) to the impeller (22a), and a drive part casing (13) in which the drive part (12) is installed. This turbocompressor (4) includes an impeller casing (22e) installed around the impeller (22a), and a gear casing (33) configured to be formed independently of the impeller casing (22e) and the drive part casing (13), to couple the impeller casing (22e) and the drive part casing (13), and to form an accommodation space (33a) in which the plurality of gears (31, 32) are accommodated. With this configuration, in manufacturing the turbocompressor, a working process can be simplified and working labor and cost can be reduced.