The electrical connection box is provided with a movable cover, a fixed cover and a main body housed in the movable cover and the fixed cover. The main body is provided with a maintenance face for the attachment of a wiring and an electrical component and is detachably attached to the movable cover. The movable cover covers the main body so that the maintenance face thereof is exposed. The movable cover slides sideways into the fixed cover and is detachably attached to the fixed cover. The fixed cover covers the maintenance face.