Exhaust bypass device and turbocharger

An exhaust bypass device comprising:

• an actuator for reciprocating a driving-rod in an axial direction;
• a support shaft rotatably supported in a housing;
• a connection link having one end portion and the other end portion, wherein the one end portion is rotatably connected to a tip portion of the driving-rod, and the other end portion is fixed to one end portion in the axial direction of the support shaft;
• a waste gate valve connected to the other end portion in the axial direction of the support shaft;
• and
• a compressive coil spring disposed between the housing and the connection link, and having a coil diameter that varies along the axial direction, wherein
• a support cylinder having a cylindrical shape is fixed to the housing, and the compressive coil spring is disposed between the housing and the connection link, on outer side of the support cylinder in a radial direction, and
• the support cylinder has one end portion in an axial direction protruding toward the connection link from an end surface of the housing, and the compressive coil spring is disposed on an outer side of an outer circumference surface of the support cylinder.