A vertical boat for holding a plurality of semiconductor wafers comprising two end members (5) positioned at the top and the bottom of the vertical boat, and a plurality of support members (3,4) vertically mounted on the end members (5), the support members (3,4) including two front support members (3) located on the wafer inserting side and at least one rear support members (4) located on the rear side of the boat, each support member (3,4) having a series of slits (3a,4a) formed thereon at a predetermined interval and a series of support portions defined by the slits (3a,4a) for supporting semiconductor wafers (1), wherein the front support member (3) is generally formed by a circular arc plate, and wherein each angle (A,B) formed between the wafer inserting direction (X) and a line linking the front end (3b) of the support portion of the front support member (3) to the center (1a) of the wafer (1) is 100 degrees or more.