An insulation device for a low-temperature pipe, the insulation device comprising: a pair of primary insulation materials surrounding a first radially outer surface and a second radially outer surface of the pipe; a pair of secondary insulation materials surrounding outer surfaces of the primary insulation materials; a pair of tertiary insulation materials surrounding outer surfaces of the secondary insulation materials; and a pair of finishing covers surrounding outer surfaces of the tertiary insulation materials, wherein the pair of secondary insulation materials are configured such that each of opposed contact surfaces thereof is formed in a shape bent at least one time, wherein a low-density foam insulation material is made of a foam material having a lower density than that of the secondary insulation materials, and covering each of lengthwise opposite ends of each of the secondary insulation materials and tertiary insulation materials, wherein each of the primary insulation materials is produced to have a shorter length than that of each of the secondary insulation materials, so that lengthwise opposite ends of the primary insulation material are located at positions inward from those of the secondary insulation material, and wherein a high-density foam insulation material is further provided, the high-density foam insulation material being in intimate contact with a lengthwise end of each of the primary insulation materials so as to cover a portion of the outer surfaces of the pipe that is not covered by the primary insulation material, and having a side protruding farther than an outer surface of the low-density foam insulation material. a pair of primary insulation materials surrounding a first radially outer surface and a second radially outer surface of the pipe; a pair of secondary insulation materials surrounding outer surfaces of the primary insulation materials; a pair of tertiary insulation materials surrounding outer surfaces of the secondary insulation materials; and a pair of finishing covers surrounding outer surfaces of the tertiary insulation materials, wherein the pair of secondary insulation materials are configured such that each of opposed contact surfaces thereof is formed in a shape bent at least one time, wherein a low-density foam insulation material is made of a foam material having a lower density than that of the secondary insulation materials, and covering each of lengthwise opposite ends of each of the secondary insulation materials and tertiary insulation materials, wherein each of the primary insulation materials is produced to have a shorter length than that of each of the secondary insulation materials, so that lengthwise opposite ends of the primary insulation material are located at positions inward from those of the secondary insulation material, and wherein a high-density foam insulation material is further provided, the high-density foam insulation material being in intimate contact with a lengthwise end of each of the primary insulation materials so as to cover a portion of the outer surfaces of the pipe that is not covered by the primary insulation material, and having a side protruding farther than an outer surface of the low-density foam insulation material.