Turbocharger gas casing and turbocharger

A turbocharger gas casing of a turbine for a turbocharger, comprising:

• a scroll part forming a plurality of scroll passages at a same position in an axial direction of the turbine,
• wherein the plurality of scroll passages include a first scroll passage,
• wherein the first scroll passage is configured so that an extension line of a line segment connecting a farthest position from a rotational axis of the turbine at an inlet for an exhaust gas of the first scroll passage and a position of a tip of a tongue part formed on an inner peripheral side of the first scroll passage does not intersect a rotor blade of the turbine in a cross section of the turbine orthogonal to the axial direction,
• wherein a first scroll passage includes a first scroll passage part extending along a circumferential direction of the turbine, and
• wherein the first scroll passage is formed such that a ratio H/W of a passage height H in the axial direction to a passage width W in a direction orthogonal to the axial direction increases toward a downstream side of the first scroll passage part.