A power transmission device includes a pulley constituting a driving-side rotor, an inner hub, a washer and a limiter which constitute a driven-side rotor, and a plate configured as a linking elastic member that connects the driving-side rotor and the driven-side rotor. A flat spring that elastically deforms in a direction along a rotation shaft is adopted as the plate. A distance in an axial direction between a pulley-side attachment portion of the plate which is attached to the pulley and a hub-side attachment portion of the plate which is attached to the inner hub is adjusted to fall within a predetermined standard range by interposing a shim as an adjustment member between the plate and the pulley.