Power transmission mechanism and exhaust heat recovery apparatus

A power transmission mechanism that transfers power from an output shaft disposed in sealed-off space within a external combustion engine, comprising:

• a drive shaft to which the power from the output shaft is transmitted;
• a first magnet that is fitted to the drive shaft and that rotates together with the drive shaft;
• a second magnet that is fitted to a driven shaft arranged concentrically with the drive shaft, that is disposed outside the sealed-off space, and that faces the first magnet;
• a partition wall that is interposed between the first magnet and the second magnet, and that separates a drive shaft side space and a driven shaft side space from each other;
• and
• a conversion unit provided between the output shaft and the drive shaft, and which adjusts a torque from the output shaft and transfers the adjusted torque to the drive shaft,
• wherein the conversion unit is a speed increasing unit that reduces the torque from the output shaft by increasing a rotational speed of the output shaft and transfers the reduced torque to the drive shaft.