To provide a protective structure for water pipe wall in which a gap, through which a water pipe wall which is formed by connecting water pipes arranged in a furnace to each other through a fin and a refractory heat- resistant block which protects the water pipe wall do not exert forces against each other, exists between the water pipe wall and heat-resistant block.

In this protective structure, a metallic pedestal 121 having a hook section 122 is installed to a base part 123 which is inserted between the water pipes 101 and 102 and the base part 123 is fixed to the fin 111 and engaged with a supporting hole 107 bored into the refractory heat-resistant block 103.