A dial apparatus includes an operation member to be rotatably operated, a contact member including a plurality of contact portions and configured to rotate as the operation member rotates, and a substrate having a signal pattern provided on a plurality of concentric circles with a center at a rotation center of the operation member. The dial apparatus outputs a binary code when the plurality of contact portions contact the signal pattern as the operation member rotates. The signal pattern includes a reference signal area connected to a reference potential, a first signal area configured to output a first signal, and a second signal area configured to output a second signal. Two of the plurality of contact portions are provided on a predetermined concentric circle in the signal pattern and contact a signal pattern that includes the reference signal area and the first signal area.