The Spirit Dance ritual of the Mon in Bang Kradi is based on two types of spiritual beliefs. The first one is in the existence of guardian spirits, which are believed to protect villagers from evil and sickness. These spirits include Bang Kradi Spirit, Hua Rahan Spirit and Thai Thung Spirit, who are respected by and have become spiritual refuges of the residents. The second one is the ancestral spirits, which are patrilineally transmitted from generation to generation. Each clan has its own ancestral spirits. It is believed that if a family or clan member violates taboos, clalamities would befall on the violator or his/her family members. The spirits are a spiritual refuge of family or clan members and an appeasement ritual is conducted annually. The fear of angering the spirits has strengthened a family bond and community solidarity. The study findings revealed that the dance ritual was originally conducted in the family when a member violated familial or social taboos. The preparation and steps of the ritual are very detailed and time-consuming. The ritual brings members of the same spirit to work together. The ritual involves a dance accompanied by traditional music. Once the ritual is conducted, it is believed that calamities that would befall on the family would be averted. The transference of the dance ritual is informal and transmitted by word of mouth, observing the actural ritual and practicing the ritual.