A mount apparatus on which an accessory is detachably mountable, the mount apparatus comprising: a mount portion ; a plurality of claw portions (201a - 201c) disposed in a circumferential direction of the mount portion ; and a restricting member arranged to restrict relative rotation of the plurality of claw portions (201a - 201c) and a plurality claw portions (301d - 301f) of the accessory , wherein the plurality of claw portions (201a - 201c) on the mount portion includes a first claw portion , a second claw portion , and a third claw portion , an angle range of the second claw portion and the third claw portion , in the circumferential direction of the mount portion is smaller than that of the first claw portion , disposed following the circumferential direction of the mount portion , and wherein, in a case of viewing the mount apparatus from the center axis direction of the mount portion , a line through the center axis direction of the mount portion and overlapping the restricting member is taken as a second mount center line , and a line through the center axis direction of the mount portion and orthogonal to the second mount center line and the mount center axis direction is taken as a first mount center line , wherein, when viewing the mount portion from the center axis direction of the mount portion , in a normal position of the mount apparatus , the first claw portion is located on the first mount center line and disposed on an upper side opposite to the gravitational direction across the second mount center line and not disposed on a lower side including the gravitational direction across the second mount center line , and wherein, when viewing the mount portion from the center axis direction of the mount portion , at least one of the second claw portion and the third claw portion is located on the second mount center line , and is arranged on an opposite side of the restricting member in relation to the first mount center line . a mount portion ; a plurality of claw portions (201a - 201c) disposed in a circumferential direction of the mount portion ; and a restricting member arranged to restrict relative rotation of the plurality of claw portions (201a - 201c) and a plurality claw portions (301d - 301f) of the accessory , wherein the plurality of claw portions (201a - 201c) on the mount portion includes a first claw portion , a second claw portion , and a third claw portion , an angle range of the second claw portion and the third claw portion , in the circumferential direction of the mount portion is smaller than that of the first claw portion , disposed following the circumferential direction of the mount portion , and wherein, in a case of viewing the mount apparatus from the center axis direction of the mount portion , a line through the center axis direction of the mount portion and overlapping the restricting member is taken as a second mount center line , and a line through the center axis direction of the mount portion and orthogonal to the second mount center line and the mount center axis direction is taken as a first mount center line , wherein, when viewing the mount portion from the center axis direction of the mount portion , in a normal position of the mount apparatus , the first claw portion is located on the first mount center line and disposed on an upper side opposite to the gravitational direction across the second mount center line and not disposed on a lower side including the gravitational direction across the second mount center line , and wherein, when viewing the mount portion from the center axis direction of the mount portion , at least one of the second claw portion and the third claw portion is located on the second mount center line , and is arranged on an opposite side of the restricting member in relation to the first mount center line . <EOS>