The utility model discloses a micro switch-on controller of a booster, and aims to provide a device for accurately and effectively transmitting power to a contact of a micro switch to realize on-off of the micro switch. According to the technical scheme, an adjusting screw facing a microswitch contact and a compression spring located below the adjusting screw are assembled on an L arm at the top end of a transmission arm, and the other end of the compression spring is fixed to a tailstock; a rectangular open groove which is connected downwards and extends in the length direction of the rectangular end face of the transmission arm is formed in the plane of the sunken end of the right side of the adjusting screw, the locking bolt is screwed in from top to bottom through the locking piece andthe rectangular open groove, and the locking piece assembled below the locking bolt is fixed to the end face of the rectangular open groove of the transmission arm. In the screwing-in process of thelocking bolt, the locking piece and the rectangular open groove generate locking force to change the adjusting screw into interference fit; the rotating shaft drives the transmission arm to deflect under the action of crank force, and the driving spring drives the adjusting screw to reciprocate to control on-off of the microswitch.