Turbine housing, turbocharger, and gasoline engine

A turbine housing configured to house a turbine wheel to be driven with exhaust gas discharged from a gasoline engine, comprising:

• a body part including a scroll passage wall surface, an exhaust gas discharge path wall surface, and a wastegate passage wall surface provided inside the body part,
• the scroll passage wall surface forming a scroll passage having a scroll shape for guiding the exhaust gas to the turbine wheel,
• the exhaust gas discharge path wall surface forming an exhaust gas discharge path for discharging the exhaust gas having passed through the turbine wheel,
• the wastegate passage wall surface forming a wastegate passage connecting the scroll passage and the exhaust gas discharge path to each other while bypassing the turbine wheel;
• and
• an entrance flange part provided at an upstream end of the scroll passage in the body part, the entrance flange part including an exhaust gas inlet leading to the scroll passage, wherein
• the wastegate passage has an entrance-side opening edge formed at the scroll passage wall surface and provided at a position where the entrance-side opening edge is visually recognizable at least partially from outside the turbine housing through the exhaust gas inlet,
• wherein the entrance-side opening edge includes a stress concentration part provided at a downstream end portion including a downstream end at the entrance-side opening edge and configured to cause concentration of stress resulting from thermal elongation.