To make the structure compact and lightweight and to improve workability in installation and operability in execution of excavation work for an apparatus and a method for excavating vertical shaft.

With the present vertical shaft excavating method, a support plate 21 laid at a specified position is fixed to the ground G with four pile members 31 penetrating through the support plate 21 thrust into the ground G, and an all casing excavator 11 is fixed to the ground G through the support plate 21 with the all casing excavator 11 mounted on the support plate 21 so that grounding plates of leg parts 13 can be inserted into indented parts and furthermore, reaction force arising from turning and swing of a casing tube 10 on excavation of a vertical shaft is received with the pile members 31 through the support plate 21.