Drive assist device, and vehicle using drive assist device

A drive assist device (100) includes a light source (6) that irradiates a detection target with light, a first lens (1) having a first area (F1) through which the irradiated light from the light source (6) passes, a second lens (2) having a second area (F2) through which reflected light reflected from the detection target passes, and a light receiving element (8) that receives the reflected light that passes the second lens (2). The first area (F1) and the second area (F2) are arranged to be in align with each other, in width direction of the drive assist device (100).