To manufacture a heat insulation apparatus easily inexpensively with a simplified construction.

In a heat insulation apparatus 5 for a combustion chamber 15 of gas turbine installation including heat insulation elements 20 disposed on a support structure 10 covering a flat plane and anchored to the support structure 10, there is formed a cooling air passageaway 30 between an anti-high temperature gas side surface and the support structure 10 of at least two adjacent heat insulation elements 20a, 20b with the two heat insulation elements 20a, 20b, to which passageaway 30 cooling air L is supplied, and the adjacent heat insulation elements 20a, 20b are communicated with each other through the cooling air L. The individual heat insulation elements 20 are assembled into the configuration of the cooling air passageaway 30 to collect the cooling air L supplied to the cooling air passageaway 30 and introduce it into a burner 70.