To make it possible to support a wafer with its load being nearly evenly dispersed to three points by forming a plurality of supporting sections in main supporters for supporting the wafer by three points and making the thickness of each of the supporting section nearly the same as that of the wafer to be supported.

A wafer boat 1 is constituted of three main supporters 2, an upper supporter 3, and a lower supporter 4. These three main supporters 2 and the upper supporter 3 and the lower supporter 4 are so formed as to be assembled and disassembled by specified stoppers at an upper and a lower end of each of the main supporters 2. In the three main supporters 2, projecting supporting sections 2a are formed at a plurality of levels. The supporting sections 2a of the three main supporters 2 are so formed as to be at the same levels. The projecting directions of the supporting sections 2a are all inwards. The thickness of each supporting section 2a is made nearly the same as that of a mounted wafer 'a' or the thickness of the wafer 'a' ±10% or about. Therefore, the wafer 'a' can be supported with its load being dispersed evenly to the three main supporters.