We propose a task recognition method for recognizing task performed by caregivers using autonomous mobile wheelchairs equipped with automatic stop and movement functions. Task locations and times are defined as a task history, and task information is based on this task history, referring to the “Spatial Memory” of Niitsuma et al. We propose a task recognition method that considers estimation error of localization at actual sites, and evaluated this method using data with simulated error added to worker's position data.