A power transmission device is provided with: a rotary body arranged to receive the torque to rotate about an axis; a clutch including a clutch member engaging with the rotary body and axially movable and clutch teeth connectable with the clutch member to transmit the torque; a solenoid configured to generate a magnetic flux in response to input of electric power; a stator coupled with the solenoid as to conduct the magnetic flux and prevented from rotation about the axis; a rotor arranged to receive the magnetic flux from the stator and, when driven by the received magnetic flux, to create a rotational motion about the axis; and a conversion mechanism drivingly connected with the rotor to convert the rotational motion into a linear motion in a direction along the axis, the conversion mechanism including a thrust member transmitting the linear motion to the clutch member.