To provide a supplementary tool for flower arrangement capable of reliably supporting a trunk leg in a vase, and capable of easily arranging beautiful standing flowers or Rikka.

The supplementary tool for flower arrangement includes: an inner cylinder container 5 arranged in the vase 1 and formed in a bottomed cylinder shape with an upper end being open; a first fixing member 61 inserted from the opening of the inner cylinder container 5 and provided at the lower end of a column 2; and a second fixing member 62 provided in the column 2 positioned in the inner cylinder container 5, and arranged with a predetermined space away from the first fixing member 61. The first fixing member 61 and the second fixing member 62 are formed so that contour shapes fit a horizontal cross-sectional shape of the inner cylinder container 5. The column 2 is arranged at a position eccentric from an axial line L of the inner cylinder container 5. A pinholder 10 is arranged in the second fixing member 62 formed of a circular plate, and a bar-like member 7 is inserted in a gap with an inner circumferential surface of the inner cylinder container 5, thus further strengthening the fixture by the second fixing member 62.