PROBLEM TO BE SOLVED: To reduce load of a worker in case when vines grow.SOLUTION: A roof greening device for greening a roof by thickly growing a vine plant along the surface of the roof is provided. The device has a lower net-like member (lower metal net 3) and an upper net-like member (upper metal net 4). The lower net-like member is installed over the roof surface with a space along the roof surface. The upper net-like member is installed above the lower net-like member with a space to form the space 43 for thickly growing the vine plant 18.