A centrifugal compressor comprising: a drive gear; a drive shaft protruding from one side of the drive gear in a central axis direction of the drive gear; a no. 1 driven pinion gear configured for rotation of the drive gear to be transmitted thereto; and a no. 1 driven pinion shaft protruding from both sides of the no. 1 driven pinion gear in a central axis direction of the no.1 driven pinion gear; a couple of first stage compressor sections, each of which is provided in each end of the no. 1 driven pinion shaft and is configured to compress fluid by rotation of the no.1 driven pinion shaft; a no.2 driven pinion gear configured for rotation of the drive gear to be transmitted thereto; a no.2 driven pinion shaft protruding from the no.2 driven pinion gear in a central axis direction of the no.2 driven pinion gear; a second stage compressor section provided to the no.2 driven pinion shaft; a heat exchanger provided to a pipe connecting the pair of the first stage compressor sections and the second stage compressor section, the heat exchanger exchanging heat of the fluid discharged from the pair of the first stage compressor sections, and wherein the heat exchanger comprises: two inlets, each of which is connected to each of the pair of the first stage compressor sections; and an outlet connected to the second stage compressor section, characterised in that the centrifugal compressor further comprises: a no.1 idle gear provided between the no.1 driven pinion gear and the drive gear; a no.2 idle gear provided between the no.2 driven pinion gear and the drive gear; and wherein rotation axes of the no.1 idle gear and the no.2 idle gear are positioned offset downward relative to a central level of the drive gear in a vertical direction. a drive gear; a drive shaft protruding from one side of the drive gear in a central axis direction of the drive gear; a no. 1 driven pinion gear configured for rotation of the drive gear to be transmitted thereto; and a no. 1 driven pinion shaft protruding from both sides of the no. 1 driven pinion gear in a central axis direction of the no.1 driven pinion gear; a couple of first stage compressor sections, each of which is provided in each end of the no. 1 driven pinion shaft and is configured to compress fluid by rotation of the no.1 driven pinion shaft; a no.2 driven pinion gear configured for rotation of the drive gear to be transmitted thereto; a no.2 driven pinion shaft protruding from the no.2 driven pinion gear in a central axis direction of the no.2 driven pinion gear; a second stage compressor section provided to the no.2 driven pinion shaft; a heat exchanger provided to a pipe connecting the pair of the first stage compressor sections and the second stage compressor section, the heat exchanger exchanging heat of the fluid discharged from the pair of the first stage compressor sections, and wherein the heat exchanger comprises: two inlets, each of which is connected to each of the pair of the first stage compressor sections; and an outlet connected to the second stage compressor section, characterised in that the centrifugal compressor further comprises: a no.1 idle gear provided between the no.1 driven pinion gear and the drive gear; a no.2 idle gear provided between the no.2 driven pinion gear and the drive gear; and wherein a no.1 idle gear provided between the no.1 driven pinion gear and the drive gear; a no.2 idle gear provided between the no.2 driven pinion gear and the drive gear; and wherein rotation axes of the no.1 idle gear and the no.2 idle gear are positioned offset downward relative to a central level of the drive gear in a vertical direction.