Autonomous mobile robots are increasingly utilized across various industries, creating environments where humans and robots coexist. To minimize discomfort and prevent robots from unnecessarily distracting humans, the management of robot behaviors must take account of the conditions (i.e., position and activity) of both humans and robots. To address this challenge, in this paper, we focus on designing appropriate movements for robots based on human perceptions of personal space in relation to robots. Previous works on personal space perceptions in relation to robots typically considered humans in static conditions, such as standing or sitting. However, in environments such as offices, humans are often seated and performing tasks. During task performance, humans’ attention is directed toward their work, potentially altering their perceptions of personal space. In this study, we examine the effect of human conditions – whether standing, sitting, sitting at a desk, or sitting at a desk while performing a task – on their perceptions of personal space in relation to an autonomous mobile robot. The experiment measured personal space distances as a robot approached participants from eight directions. The results indicated that the participants’ perceptions of personal space in the presence of the robot varied depending on their conditions, including posture and task engagement. Specifically, in the task condition, where participants performed a typing task on a laptop, personal space was positioned closer to the front and slightly elongated, reflecting the influence of task-focused attention.