PURPOSE: To easily and safely remove astringent material of tea attached to the grate board of a rolling and drying drum of a tea-processing machine and to improve the tea-processing efficiency and tea quality by using a specific apparatus.

CONSTITUTION: A number of bamboo strips are closely laid on the bottom of a rolling and drying drum of a tea-processing machine. The rolling bottom part covered with the bamboo strips 9 is divided into sections 1-8 and a back plate is fixed to each section 1 to 8 and detachably fixed to the rolling and drying drum as a grate board. When astringent material of tea is attached to the bamboo strips 9 after the operation of the tea-processing machine for a prescribed period, the grate boards of the sections 1-8 are exchanged with reserve grate boards. The grate board stained with the astringent material is immersed in water filled in a water tank to remove the astringent material.