This paper presents a compliant monolithic multistable actuator which is able to switch its moving part between several stable positions linearly in one dimensional direction. The number of stable positions can be increased by extending the range of displacement of the moving part. The transition in each step of displacement is made to the nearest stable position in the direction of motion. Upward and downward steps are made by a specific sequence of moving, using a bistable module, opening and closing two internal clamps which are actuated by U-shaped electrothermal actuator using three subsystems. The principle and the design of each subsystem in the discrete acruator, fabrication process and experimental results are presented. The fabricated prototypes of the discrete actuator showed a proper functioning. The mean achieved displacement is 120.67±0.08 µm over 12 upward steps with a mean step of 10.06 µm, which is very close to the designed performance.