To provide a spectacle lens machining device, which thins an edge of a lens edge shoulder connected to a rear face lens edge, and reduces the sharpness of the edge in a simple configuration.

In the spectacle lens machining device including a lens chuck shaft holding a spectacle lens, and the lens edge machining tool forming a lens edge in a rim of the spectacle lens held by the lens chuck shaft, the lens edge machining tool has a first machining portion forming a lens edge on a lens rear face side, and a second machining portion forming the lens edge shoulder to be connected to the rear face side lens edge, and in the second machining portion, a distance yn from a line passing through a boundary point and in parallel with an axis of the lens chuck shaft is gradually increased until the end point of the second machining portion is reached from the boundary point with the first machining portion as a start point, and an increase rate of the distance yn is gradually increased at least two stages toward the end point.