<;P>;PROBLEM TO BE SOLVED: To provide a shaft coupling structure for coupling a ventilation sheet winding shaft to a rotary machine output shaft, which couples a sheet winding shaft in a ventilation device by which a ventilation sheet at the side surface or the valley part of an agricultural plastic house is wound up to make an opening or wound down to close the opening, to the output shaft of a rotary machine functioning as a rotary power means; and to provide a shaft coupling member used in the shaft coupling structure. <;P>;SOLUTION: The shaft coupling member 3 is structured as a pipe body where a socket part 31 with which the output shaft 4 of a rotary machine 2 is engaged, and a socket part 32 with which a sheet winding shaft 1 is engaged, are separated via a dividing wall 33 in an uncommunicated structure. A drainage flange 34 rises at the outer peripheral surface of the shaft coupling member 3 in a sword guard state. The output shaft 4 of the rotary machine 2 and the sheet winding shaft 1 respectively engaged with the socket parts 31, 32 are fixed via locking screws 8, 9 respectively. A drainage hole 35 pierced through to the outer peripheral surface is made at a position in the vicinity of the inner end of the socket part 32 with which the sheet winding shaft 1 is engaged. <;P>;COPYRIGHT: (C)2010,JPO&INPIT