Patent ID: 7903966

Claim:
An accessory device configured to be mounted on an accessory shoe of an image pickup apparatus, the accessory device comprising: an insertion member configured to be inserted in an engagement space around by a first engagement part, a second engagement part and a third engagement part of the accessory shoe, the insertion member holds a contact for electrically connecting a contact part of the image pickup apparatus which is provided in the engagement space; an operating member configured to perform an operation for fixing the accessory device on the accessory shoe in a state where the insertion member is inserted in the engagement space; and a moving member configured to move in a second direction intersecting with a first direction in which the insertion member is inserted in the engagement space by the operation of the operating member, wherein the third engagement part is formed in a direction opposite to the first direction to cover the contact part of the image pickup apparatus which is provided in the engagement space, and wherein the moving member is provided with a protrusion part which is in contact with at least one of a groove formed between the first engagement part and the third engagement part and a groove formed between the second engagement part and the third engagement part so that the insertion member is not removed from the engagement space by a movement of the moving member in the second direction.