PURPOSE: To increase productivity by manufacturing a fiber reinforced plastic grid from a truss beam including a pair of parallel chord members and a series of shear members arranged between the chord members, so as to shift the fiber reinforced shear members to the chord members at a nodal point between the shear and chord members.

CONSTITUTION: Two truss beam 10, 20 including a pair of parallel fiber reinforced plastic chord members 11, 12 and 21, 22, and a series of parallel fiber reinforced plastic shear members 13, 23 arranged between the respective chord members, are arranged on two parallel vertical surfaces, and both of 10 and 20 are connected to each other by using a cross member 30 and a diagonal member 31 which pass respective upper chord members 11, 12 and are within the horizontal surface. In manufacturing the truss beam 10, for example, resin impregnated bundles are arranged from the first nodal point 1 to the second nodal point 2 by an arm to manufacture the first shear member 13. The arm is then moved toward the third nodal point to manufacture part of the upper chord member 11. The arm is continuously moved as indicated by an arrowhead to complete its manufacture.