Dial unit and introduction apparatus

The dial unit includes a dial including a shaft and being rotatable around the shaft, a detector to detect a rotation amount of the dial, a rotator engaged with the dial and rotatable together with the dial. The dial unit includes a rotation transmission member to keep the dial and the rotator separated from each other before the rotation angle of the dial reaches a first angle and to transmit rotation of the dial to the rotator when the rotation angle exceeds the first angle. The dial unit includes an elastic member which is shaped as a coil-shaped portion and contains the rotator inside the coil-shaped portion. The elastic member applies to the rotator a torque in an opposite direction to a rotational direction of the rotator when the rotator rotates.