To provide a slope scaffolding device in which, while remarkably improving safety and workability of a main body (work platform), economical efficiency can also be improved remarkably.

A slope scaffolding device 1 comprises: a form 2 formed from a bundle material erected to a slope S; a temporary joist material 10 placed on the form and disposed along the slope; a scaffolding form supporting beam 15 communicated to the temporary joist material and disposed substantially along the slope: a scaffolding form depth material 16 connected to the scaffolding form supporting beam and/or the temporary joist material and disposed substantially in a horizontal direction opposing the slope; and fitting position varying mechanisms 11, 12 and 13 which are connected to fit the temporary joist material and the scaffolding form supporting beam and in which the position of fitting is variable.