Abstract: The present invention provides a clutch structure of mirror adjustment mechanism comprising a clutch driving gear with specified gear teeth formed at circumference thereof and hollow fitting chuck formed at center thereof, to be geared with the output axis of a driving motor via a gear train, whereby the fitting chuck is divided by a plurality of slits in circumferential direction and a donut-shape groove is formed collapsed between the gear teeth and the fitting chuck; a pinion gear including a protrusion at one end thereof, to be geared with a rack gear formed at one side of the adjustment member, whereby the protrusion is inserted into the inner surface of the fitting chuck; and a spring pin that provides frictional contact on the contact surface between fitting chuck of the clutch driving gear and protrusion of the pinion gear by applying bias force in radial direction while it is inserted in the groove of the clutch driving gear, or allows slip movement.