This study is for the purpose of clarifying which conditions the behavior of avoiding strangers is influenced by, by taking up the case of pedestrians passing unfamiliar stranger as issues concerning safety and amenity on the streets at night. We have first of all carried out the experiment of presenting video images. As a result, there was the tendency of avoiding strangers earlier in bright streets with high visibility compared to dark streets toward oncoming strangers approaching head-on on the same axis without avoiding. There was also the tendency of starting avoidance at a point when the vertical illuminance of the oncoming stranger's face has become high. Secondly, we have conducted an observation and experiment on an actual street. As a result, there were tendencies for more female than male pedestrians to start avoidance of oncoming strangers earlier, and male oncoming strangers being avoided earlier.
