A building exterior insulation structure, comprising: a first board member disposed on an exterior side of a framework forming a building, the first board member extending in a first direction and a second direction substantially perpendicular to the first direction; a plurality of first supporting members disposed on the exterior side of the first board member ; at least one first thermal insulator disposed on the exterior side of the first board member and between the first supporting members ; a plurality of second supporting members (82; 282) disposed on the exterior side of the first supporting members , the second supporting members (82; 282) extending in the first direction and being spaced apart from one another in the second direction; and at least one second thermal insulator disposed on the exterior side of the first thermal insulator and between the second supporting members (82; 282); a plurality of securing members fixed to the exterior side of the second supporting members (82; 282) and extending in the second direction; and a plurality of exterior wall members (2; 202) attached to the securing members to cover the framework , wherein the exterior wall members (2; 202) adjacent to each other are joined together without leaving a gap therebetween, wherein a length (L10) of each securing member in the second direction is determined so as to be long enough to be fixable to at least two of the second supporting members (82; 282) and so as to be shorter than a length (L2) of each exterior wall member (2; 202) in the second direction, wherein a first gap (W1; W21) is left between each two of the securing members adjacent to each other in the second direction, the first gap (W1; W21) falling within a range of approximately 10 mm to 300 mm, and wherein at least part of each second supporting member (82; 282) is made of a material having a thermal conductivity lower than that of steel. a first board member disposed on an exterior side of a framework forming a building, the first board member extending in a first direction and a second direction substantially perpendicular to the first direction; a plurality of first supporting members disposed on the exterior side of the first board member ; at least one first thermal insulator disposed on the exterior side of the first board member and between the first supporting members ; a plurality of second supporting members (82; 282) disposed on the exterior side of the first supporting members , the second supporting members (82; 282) extending in the first direction and being spaced apart from one another in the second direction; and at least one second thermal insulator disposed on the exterior side of the first thermal insulator and between the second supporting members (82; 282); a plurality of securing members fixed to the exterior side of the second supporting members (82; 282) and extending in the second direction; and a plurality of exterior wall members (2; 202) attached to the securing members to cover the framework , wherein the exterior wall members (2; 202) adjacent to each other are joined together without leaving a gap therebetween, wherein a length (L10) of each securing member in the second direction is determined so as to be long enough to be fixable to at least two of the second supporting members (82; 282) and so as to be shorter than a length (L2) of each exterior wall member (2; 202) in the second direction, wherein a first gap (W1; W21) is left between each two of the securing members adjacent to each other in the second direction, the first gap (W1; W21) falling within a range of approximately 10 mm to 300 mm, and wherein at least part of each second supporting member (82; 282) is made of a material having a thermal conductivity lower than that of steel. <EOS>