A micro-sensor device that includes a passivation-protected ASIC module and a micro-sensor module bonded to a patterned cap provides protection for signal conditioning circuitry while allowing one or more sensing elements in the micro-sensor module to be exposed to an ambient environment. The knife holder has a wing part at two opposite lateral sides thereof respectively and two frame plates at a lower portion thereof with a frame groove in between. Either one or both of the first adjusting screw and the second adjusting screw are rotated to move the fixed height position of the upper belt under the swinging action about the support point on a lower circular arc-shaped section of the fixing member.