The invention discloses a mechanical brake device. The device is mainly connected to a brake cable and includes a cylinder body, a piston assembly, multiple bead bodies, two brake discs and two control assemblies; each braking member can be driven to do axial displacement in the assembly hole of each threaded ring member by each control assembly; and the matching of each braking member and location holes are in spiral rotation displacement through each bead body. Through the linkage arrangement of each control assembly, the clamping brake motion of each brake disc can be further pushed; and through the arrangement of the multiple bead bodies, the clamping brake force of each brake disc can be increased, so that reliable and stable braking can be achieved.