A powder chamber (10) for an air polisher (90) extending along an axis (c) from a top end (t) to a bottom end (b), the powder chamber (10) comprising at least two walls Portions (11, 12), the first wall portion (11) forms a first angle (α 11 ) with respect to the axis (c), and the second wall portion (12) is The angle measurement direction (md) from the axis (c) to the corresponding wall portion (11, 12) is such that the angle (α 12 ) is 2 and the angles (α 11 , α 12 ) are acute angles, The direction from the top end (t) to the bottom end (b) is positive, the direction from the bottom end (b) to the top end (t) is negative, and the second wall portion (12) is The second angle (α 12 ) is smaller than the first angle (α 11 ), and is disposed below the first wall portion (11). [Selection] Figure 6頂端部（ｔ）から底端部（ｂ）まで軸（ｃ）に沿って延在する空気研磨装置（９０）用粉末室（１０）であって、当該粉末室（１０）は少なくとも２つの壁部分（１１，１２）備え、第１の壁部分（１１）は軸（ｃ）に対し第１の角度（α１１）をなし、第２の壁部分（１２）は軸（ｃ）に対し第２の角度（α１２）をなし、角度（α１１、α１２）それぞれが鋭角となるように、軸（ｃ）から該当する壁部分（１１、１２）までの角度計量方向（ｍｄ）は、頂端部（ｔ）から底端部（ｂ）までは正値の方向とし、底端部（ｂ）から頂端部（ｔ）までは負値の方向とし、第２の壁部分（１２）は第１の壁部分（１１）の下方に配置され、第２の角度（α１２）は第１の角度（α１１）よりも小なることを特徴とする。【選択図】図６
