Agrivoltaics—the integration of solar photovoltaic systems with agriculture—is a growing trend worldwide. Although studies have clarified the effects of photovoltaic panels above farmland on microclimate and crops, their impact on the organisms within farmland remains poorly documented. Assessing the influence of agrivoltaic installations on organisms within farmland is crucial, as biodiversity and beneficial arthropods that prey on pests can positively affect crop yields. This study assessed the effects of agrivoltaic structures on orb-weaving spiders, which are beneficial arthropods, in Chiba City, Chiba Prefecture, Japan. Over four investigations conducted from June to September 2023, we discovered that the vertical distribution of orb-weaving spiders was concentrated in the structural braces within the photovoltaic panel framework. In terms of horizontal distribution, spiders were most prevalent in areas adjacent to forests, where prey insects were relatively abundant. These findings suggest that agrivoltaic structures, which are typically absent on farmland, can serve as scaffolding for orb-weaving spiders and that the location of web construction within agricultural fields depends on prey availability.