A processing mechanism for machining a workpiece includes a fixing base, a driving member, a connecting member, a cutter and a spring. The driving member is positioned above the fixing base. The connecting member is coupled to the driving member. One end of the cutter is fixed to the connecting member, and the cutter can be driven to pass through the fixing base to machine the workpiece positioned under the fixing base. The spring is positioned between the connecting member and the fixing base. The spring is compressed when the driving member drives the cutter away from the fixing base to machine the workpiece, and the spring under compression biases the cutter back toward the fixing base. The disclosure also supplies a processing device using the processing mechanism.