Space is decreased in the direction of thickness on a side of a substrates mounted on a back of a flat panel display to adapt requirement for increasing and thinning its size, and most flat panel displays forcibly radiate heat with a fan provided thereon. The present invention provides a flat panel display having fewer heat radiating fans to secure a channel for causing a heat radiating air to flow. Portions where electronic circuit device on a back of a display panel are mounted are divided into three: left; center; and right portions; with a main frame as a border, the electronic circuit device are constructed of four module substrates, the substrate which is the greatest in heating value in the four module substrates (hereinafter referred to as a substrate) is arranged in the center portion and the substrates which are the smallest and the second smallest in heating value therein are arranged in the same portion.