PURPOSE: To reduce a construction period by using a roof members constituted of the first cable net and the second cable net arranged on the upper and lower surfaces of a membrane member and capable of acting in separation from the membrane member, and installing a temporary roof on a construction site.

CONSTITUTION: The first cable net 3 and the second cable net 4 capable of acting in separation from a membrane member 2 are arranged on the upper and lower surfaces thereof to form an approximately rectangular roof member 1. The periphery of the roof member 1 is fixed along a pair of horizontal members, roof beam mars and ridge beam members, and the roof beam member and the ridge beam member are connected to the horizontal member through pins so that they are capable of rotation to form the first unit. The periphery of the roof member 1 is fixed along the horizontal member, a pair of roof beam member and the ridge beam member, and the horizontal member, the roof beam member and the ridge beam member are mutually connected through pins so that they are capable of rotation to form the second unit. In addition, the first unit is provided to both ends in the direction of a girder of a temporary roof and, at the same time, the second unit is provided to an intermediate position in the direction of the girder.