Multi-stage turbocharger

A multi-stage turbocharger comprising:

• a turbine housing including a first sub-housing that has a first turbine-wheel chamber and a second sub-housing that has a second turbine-wheel chamber arranged in series to the first turbine-wheel chamber;
• a first compressor housing coupled to the turbine housing via a first bearing housing;
• and
• a second compressor housing coupled to the turbine housing via a second bearing housing, wherein
• the first sub-housing and the second sub-housing are formed integrally with each other,
• the first sub-housing and the second sub-housing are connected to and are separated from each other via a second intake passage,
• the turbine housing includes
• a first intake passage and a first exhaust passage that communicate with the first turbine-wheel chamber and the second intake passage, and
• a second exhaust passage that communicates with the second turbine-wheel chamber,
• an intake side of the first intake passage, an intake side of the second intake passage, and a discharge side of the second exhaust passage are open toward a substantially same direction,
• the first sub-housing includes a first flange on which the intake side of the first intake passage and the intake side of the second intake passage are open, and
• the second sub-housing includes a second flange on which the discharge side of the second exhaust passage.