In a power transmission device, a dynamic damper is provided in a power transmission path having at least one damper disposed therein, and has an inertial rotating body that can rotate relative to a transmission rotating member forming part of the power transmission path, and a dynamic damper spring that can provide connection between the transmission rotating member and the inertial rotating body. A preset load is applied to the dynamic damper spring in a non-transmitting state of the power transmission path. The dynamic damper spring is supported on either one of the transmission rotating member and the inertial rotating body so as to apply the preset load to the dynamic damper spring in the non-transmitting state, and a gap is set in a rotational direction in the non-transmitting state between the dynamic damper spring and an other one of the transmission rotating member and the inertial rotating body.