Disclosed is an optical device which includes: an optical component configured to be electrically actuated such that a light transmission state is variable; a driver circuit for the optical component; a power source unit for driving the optical component; a rim for supporting the optical component; a temple having front and rear ends and connected at the front end to the rim; and an earpiece formed at the rear end of the temple. The power source unit includes a secondary battery, a power switch, a power switch control portion, and a use-status sensing portion for sensing the status of use by a user of the optical device. The power switch control portion performs control to turn off the power switch when the use-status sensing portion does not sense any use by the user of the optical device.