The weapon focus effect is defined as a phenomenon that when viewing an individual holding a weapon, people tend to direct their attention towards the weapon and less accurately remember peripheral details in the scene. The purpose of this paper was to review the previous studies that examined the weapon focus effect and to propose a new model that can explain the previous results. In the first part of this paper, I reviewed previous studies that explored the effect of a weapon on participants’ fixation pattern and memory accuracy for peripheral details, and I introduced arousal and unusual item hypotheses. Subsequently, I reviewed the functional field of view hypothesis, asserting that the presence of a weapon shrinks the functional field of view, resulting in impairment of memory accuracy for peripheral details. Finally, I proposed a new model that integrates the unusual item hypothesis with the functional field of view hypothesis to explain the weapon focus effect.