To provide a rearward/sideward visual recognition support device which performs visual recognition support using a Fresnel lens when needed for a rearward/sideward dead zone generated in visual recognition action, and does not hinder the visual field of a driver when not needed.

This rearward/sideward visual recognition support device 10 for performing support for visually recognizing a rearward/sideward dead zone in an automobile is configured to move and arrange a Fresnel lens 11 to/on a side window 12 when an intention of a driver to perform a lane change or right/left turn is detected, and to store the Fresnel lens 11 at the original position when the detection of the intention is ended.