An imaging apparatus, comprising: a second mount arranged to bayonet couple with a first mount on an accessory, wherein the second mount has a plurality of contact pins (203a-203k, 203m) disposed on an array line following the circumferential direction of the second mount, and arranged for electrical connection to a plurality of contact faces (303a-303k, 303m) provided on the first mount in a case that the second mount is bayonet-coupled to the first mount, the number of the plurality of contact pins (203a-203k, 203m) being an even number that is four or larger, wherein, in a normal position of the imaging apparatus where a lock pin of the imaging apparatus is situated at the right side when viewing the imaging apparatus from the second mount side to which the first mount is coupled, a line extending from a center axis of the second mount in the gravitational direction and an opposite direction from the gravitational direction is taken as a first mount center line, and a line orthogonal to the center axis and the first mount center line is taken as a second mount center line, characterized in that when viewing the imaging apparatus from a direction parallel to the center axis of the second mount, the plurality of contact pins (203a-203k, 203m) include a first contact pin that overlaps the first mount center line in the radial direction of the second mount, and the plurality of contact pins (203a-203k, 203m) include a second contact pin and a third contact pin that have substantially same distance to the second mount center line, wherein the second contact pin is a contact pin situated at an end on one side of the plurality of contact pins (203a-203k, 203m) disposed on the array line, and the third contact pin is a contact pin situated at an end on another side of the plurality of contact pins (203a-203k, 203m) disposed on the array line. a second mount arranged to bayonet couple with a first mount on an accessory, wherein the second mount has a plurality of contact pins (203a-203k, 203m) disposed on an array line following the circumferential direction of the second mount, and arranged for electrical connection to a plurality of contact faces (303a-303k, 303m) provided on the first mount in a case that the second mount is bayonet-coupled to the first mount, the number of the plurality of contact pins (203a-203k, 203m) being an even number that is four or larger, wherein, in a normal position of the imaging apparatus where a lock pin of the imaging apparatus is situated at the right side when viewing the imaging apparatus from the second mount side to which the first mount is coupled, a line extending from a center axis of the second mount in the gravitational direction and an opposite direction from the gravitational direction is taken as a first mount center line, and a line orthogonal to the center axis and the first mount center line is taken as a second mount center line, characterized in that when viewing the imaging apparatus from a direction parallel to the center axis of the second mount, the plurality of contact pins (203a-203k, 203m) include a first contact pin that overlaps the first mount center line in the radial direction of the second mount, and the plurality of contact pins (203a-203k, 203m) include a second contact pin and a third contact pin that have substantially same distance to the second mount center line, wherein the plurality of contact pins (203a-203k, 203m) include a first contact pin that overlaps the first mount center line in the radial direction of the second mount, and the plurality of contact pins (203a-203k, 203m) include a second contact pin and a third contact pin that have substantially same distance to the second mount center line, wherein the second contact pin is a contact pin situated at an end on one side of the plurality of contact pins (203a-203k, 203m) disposed on the array line, and the third contact pin is a contact pin situated at an end on another side of the plurality of contact pins (203a-203k, 203m) disposed on the array line.