This paper proposes a novel form of a three-dimensional coaxial bowtie-shaped mechanical amplifier. The proposed model incorporates a lever mechanism into the Sarrus linkage structure. It allows the target plate to move along one axis with amplified displacement in a parallel manner. The amplifier was assembled after machining the components using a computer numerical control machine. A flexible hinge was incorporated into the amplifier design for simplified fabrication and reduced friction in the actuation mechanism. Castigliano’s theorem is used to build a mathematical model of the proposed mechanical amplifier, and the performance was validated through finite element analysis and prototype fabrication. We achieved the amplification ratio of ×8.44, resulting in the axial displacement up to 86 µm. The demonstrated amplifier is expected to apply to compact microsurgical robots or biomedical imaging apparatus requiring coaxial displacement amplification in confined spaces.