To provide a device for reducing a toxic component in exhaust gas capable of substantially reducing HC and NOx of unburned fuel components in exhaust gas from an engine and of enhancing a fuel consumption ratio at the same time.

The device includes an obsidian 24 on the upstream side of an air cleaner 10 so that air coming into contact with the obsidian 24 is introduced into an engine 18 through the air cleaner 10. By so doing, HC and NOx of unburned fuel components in exhaust gas from the engine 18 can be substantially reduced, and a fuel consumption ratio can be enhanced at the same time.