For the efficient manufacturing of black tea of broken type, the operation of the Yamamasu's rolling cutter with which the fresh tea leaves were cut before withering was examined.The experimental results were as follows.1. By cutting the fresh tea leaves at the beginning of the manufacturing process, the withering time was reduced about 5 hours and the yield of tea of broken type was increased about 2-6 times than those of the usual process.2. Concerning the qualities of tea made by this method, the style of tea was remarkably improved, and the market price was elevated, but the color of infusion and infused leaf was apt to. have a dull dark color.3. The profitable operation of this cutter was decided with the clearance of the cutting edge, of 3-5mm. by testing the qualities of tea.