A shoe device of an accessory that secures necessary functions and mechanical strength when the accessory is used with attaching to an electronic apparatus and that improves convenience during use when the accessory is used without attaching to an electronic apparatus. An engagement member is attachable to and detachable from an accessory shoe device of an electronic apparatus by sliding in a first direction. A holding member holds the engagement member. An attachment part is provided in the engagement member or the holding member and allows attachment of a member different from the accessory shoe device. A connection member has connection terminals arranged in a second direction that intersects perpendicularly with the first direction and is arranged in a front of the holding member in the first direction. The attachment part is provided behind the connection terminals in the first direction.