A camera accessory comprising: a mount to which a camera having a power supply circuit and a first actuator is connectable and which includes a circular portion; and a plurality of contact surfaces (302a1-9) arranged in a circumferential direction of the mount, wherein the plurality of contact surfaces includes: a first contact surface (302a3) to be used for a communication clock signal; a second contact surface (302a4) to be used for outputting communication data to the camera connected to the camera accessory; a third contact surface (302a1) to be used for indicating type of the camera accessory, and a fourth contact surface (302a7) to be used for receiving a power supply from the camera in a state where the camera accessory is connected to the camera, characterized in that in a state where the mount is connected to the camera and the camera is in a normal position, when the mount is viewed from a direction facing the mount, a line extending from a center of the mount in a direction of gravity being defined as a mount center line; the mount center line is located between the first contact surface (302a3) and the second contact surface (302a4); the first and third contact surfaces (302a3, 302a1) are located on a first side on which the first actuator is located with respect to the mount center line; and the second and fourth contact surfaces (302a4, 302a7) are located on a second side on which the power supply circuit is located with respect to the mount center line. a mount to which a camera having a power supply circuit and a first actuator is connectable and which includes a circular portion; and a plurality of contact surfaces (302a1-9) arranged in a circumferential direction of the mount, wherein the plurality of contact surfaces includes: a first contact surface (302a3) to be used for a communication clock signal; a second contact surface (302a4) to be used for outputting communication data to the camera connected to the camera accessory; a third contact surface (302a1) to be used for indicating type of the camera accessory, and a fourth contact surface (302a7) to be used for receiving a power supply from the camera in a state where the camera accessory is connected to the camera, characterized in that in a state where the mount is connected to the camera and the camera is in a normal position, when the mount is viewed from a direction facing the mount, a line extending from a center of the mount in a direction of gravity being defined as a mount center line; the mount center line is located between the first contact surface (302a3) and the second contact surface (302a4); the first and third contact surfaces (302a3, 302a1) are located on a first side on which the first actuator is located with respect to the mount center line; and the second and fourth contact surfaces (302a4, 302a7) are located on a second side on which the power supply circuit is located with respect to the mount center line. a first contact surface (302a3) to be used for a communication clock signal; a second contact surface (302a4) to be used for outputting communication data to the camera connected to the camera accessory; a third contact surface (302a1) to be used for indicating type of the camera accessory, and a fourth contact surface (302a7) to be used for receiving a power supply from the camera in a state where the camera accessory is connected to the camera, characterized in that in a state where the mount is connected to the camera and the camera is in a normal position, when the mount is viewed from a direction facing the mount, a line extending from a center of the mount in a direction of gravity being defined as a mount center line; the mount center line is located between the first contact surface (302a3) and the second contact surface (302a4); the first and third contact surfaces (302a3, 302a1) are located on a first side on which the first actuator is located with respect to the mount center line; and the second and fourth contact surfaces (302a4, 302a7) are located on a second side on which the power supply circuit is located with respect to the mount center line.