To provide an imaging mechanism able to adjust a quantity of light without using a mechanical configuration and to provide a forward monitoring camera equipped with this imaging mechanism.

An imaging mechanism 7 provided for a forward monitoring camera adjusts a quantity of light transmitted through a liquid crystal shutter 73 arranged in an adjusting portion, thereby making it possible to adjust a quantity of light taken into an image sensor 70, without using a mechanical configuration. For example, when a quantity of light is large as in daytime, light passing through the adjusting portion is blocked, and a quantity of light taken into the image sensor 70 is hence reduced, thereby improving the resolution of an image picked up in daytime. On the other hand, when a quantity of light is small as in night time, light is passed through the adjusting portion and hence a quantity of light taken into the image sensor 70 is increased, thereby improving the brightness of an image picked up in night time.