An image-taking apparatus capable of mounting an accessory, which is small-sized yet capable of securing a sufficient inner volume is disclosed. The image-taking apparatus includes a first member having a female screw hole portion into which a male screw portion provided in the accessory is inserted, a main chassis to which the first member is fixed and a second member which covers an opening of the female screw hole portion opposite to the insertion side of the male screw portion. The female screw hole portion is a hole portion penetrating the first member and the second member prevents the male screw portion from further going in by the tip of the male screw portion inserted into the female screw hole portion contacting the second member.