The present technology relates to a wearable device and an electricity supply system that make it possible to reduce the stress on a user in relation to electricity supply. A power generating unit is provided on the external world-side surface or the eyeball-side surface of a contact lens-type wearable device. The power generating unit generates electric power by chemical reaction with a substance contained in a secretion or a body fluid of a user wearing the wearable device, and a power managing unit supplies the electric power obtained in the power generating unit to each part of the wearable device. Thus, the power generating unit performs electricity generation using the secretion or the body fluid of the user as fuel; thereby, electric power can be stably supplied, and the stress on the user in relation to electricity supply can be reduced. The present technology can be applied to a contact lens-type wearable device.