PURPOSE: To manufacture a three-dimensional truss at low cost by making a top chord of the title truss from a compound structure composed of a deformed bar and overlapped rectlineal sheet members of two expanded metals.

CONSTITUTION: Two expanded metals 8 and 8' are put together in a way that ribs 5 and 5' of the metal's rectlineal sheet members 2 and 2', positioned in the middle, and ribs 5 and 5' of the metal's rectlineal sheet members 3 and 3', positioned on both sides, are respectively fitted one another, and the metal's oblique sheet members 7 and 7' are further fitted each other. Then, each of the rectlineal sheet members 2 and 2' and 3 and 3' are made to become units by spot welding. A deformed bar 10 is then arranged at the inside of the rectlineal sheet members 2 and 2', positioned in the middle, and the sheet members 2 and 2' are clamped by a force applied from the outside, to the bar 10 to form a top chord (a). Thereby the title truss A is structured.