Due　to　the　limitations　of　geometric　and　mechanical　performances　of　fine-pitch　gears,　traditional　gear　single-flank　testing　technology　based　on　unilateral　drive　has　not　been　applied　to　the　inspection　of　fine-pitch　gears.　Heretofore　it　is　still　a　problem　to　inspect　the　transmission　error　of　fine-pitch　gears.　To　resolve　this　problem,　based　on　bilateral　drive　a　novel　principle　of　gear　single-flank　testing　for　fine-pitch　gears　is　proposed.　Based　on　this　principle,　a　measuring　machine　has　been　developed.　The　novel　measurement　principle,　measuring　machine　configuration　and　related　critical　techniques　are　introduced.　For　the　hardware,　the　measuring　machine　is　configured　with　two　parallel　spindles　driven　by　two　motors　synchronously　on　different　ends.　And　the　micro-replacement-angle　between　two　spindles　is　measured　by　a　specially　designed　measuring　device.　The　tiny　displacement　signal　is　transmitted　by　a　wireless　transmission　system　to　the　host　computer　for　data　processing.　For　the　software,　the　test　and　control　software　is　developed　with　Microsoft　Visual　C++　6.　0.　Experimental　results　show　that　the　measuring　machine　can　inspect　fine-pitch　gears　with　fast　speed.