Analyses were done on the health-related problems occurring among 12 Amyotrophic Lateral Sclerosis (ALS) patients who depend on Home Mechanical Ventilation (HMV) while social activities outside the home. The health-related problems were initially categorized according to differing scenarios of incidents. 115 incidents (50.7%) were related to do with ventilator systems. 112 incidents (49.3%) were related to do with human systems that were other than the respiratory system. Further categorization was done according to such causal factors related to environments, caregivers, attached devices, and other causes. Analyses were also done by each stage of activities: going out, while out, and on the way back home. When going out of the house, most health-related problems were caused by environmental factors such as obstacles in the house or limited spaces. During social activities, outside the home main causal factors were related to the outside environment or caregivers. When returning home, main causal factors were related to caregivers. Above findings indicate: Improvements in the home environment contribute to the decrease in the incidents that occur when going out. Skilled caregivers with the ability to deal with unexpected situations are desirable during outside activities. Support systems should be prepared for both patients and caregivers whenever they are fatigued after social activities outside the home.