A release button mechanism of a camera includes a release button which is movably provided on a camera body and which has a release cable mount, and a release pin which is supported in the release button to move in the same direction as the release button and which is adapted to transmit the movement of the release button and the movement of a release cable attached to the release cable mount. A release button association member is engaged by the release button and rotates together with the release button when the latter rotates in a plane substantially perpendicular to the direction of the movement of the release button. The camera body includes a stop to prevent the release button association member from rotating. The release button association member is provided with a restriction portion which engages with the release pin to prevent the slipping-off of the release pin from the release button.