The victims of the Great East Japan Earthquake and Tsunami have been forced to live in temporary housing, mainly by two different methods of resettlement: group allocation that preserved pre-existing local social ties and lottery allocation. We examined the effects of various factors, including the resettlement methods and social support, on mental health. From February to March 2012, we completed a cross-sectional survey of 281 refugees aged 40 years or older, who had lost their homes in the tsunami and were living in temporary housing in lwanuma city. Psychological distress of the victims was assessed using the Kessler Psychological Distress Scale (K6) that consists of six self-reported items. Participants were also asked whether they had provided or received social support during this time. Participants were categorized as "providing social support" if they listened to someone else's concerns and complaints, or "receiving social support" if they have someone who listened to their concerns and complaints. After adjusting for age and sex, multiple log-binomial regression analysis showed that participants without social support had a higher risk of psychological distress. Group allocation victims were more likely to receive social support than those who underwent lottery allocation. However, the resettlement approach did not significantly correlate with distress. Other factors associated with a higher risk of psychological distress were a younger age (55 or younger), living with either 3 people or 6 or more people, and having a lower income. The present results suggest that social support promotes the mental health of disaster victims.