A conventional alloy for a fusible plug contains a harmful element such as Cd or Pb. As a result, it has been feared that a conventional fusible plug may pollute the environment due to the harmful element. The present invention provides a fusible plug which does not contain a harmful element such as Cd or Pb, and further has a high mechanical strength such as good creep characteristics and thus is free from the phenomenon that an alloy is pushed out from the fusible plug, even when used as a safety device in a refrigerating apparatus for a long period of time. An alloy for a fusible plug which has a chemical composition that Sn: 5 to 8 mass %, Bi: 31 to 34 mass %, Sb: 0.2 to 4 mass % and the balance: In, and melts at a temperature of about 66 to 70 DEG C; and a fusible plug using the above alloy. The alloy for a fusible plug may further comprise, as a strength-enhancing element, one or more elements of 0.1 to 1.0 mass % of Cu, 0.1 to 1.0 mass % of Ge, 0.1 to 0.7 mass % of Ag, 0.1 to 0.6 mass % of Au, 0.2 to 0.6 mass % of Zn, 0.02 to 0.1 mass % of Ni, and 0.01 to 0.1 mass % of a La group element, in a total amount of 2.0 mass % or less.