To resolve a problem of a conventional hydraulic continuously variable transmission provided with a closed circuit composed by connecting a hydraulic pump and a hydraulic motor with a pair of oil circuits, and a charge circuit supplying pressure oil into the closed circuit wherein assemblability and maintainability are deteriorated since a large attachment space is needed when attaching a neutral valve, a relief valve and a check valve, and the device becomes large.

The hydraulic continuously variable transmission 1 is provided with the closed circuit 8 composed by connecting the hydraulic pump 2 and the hydraulic motor 3 with the pair of oil circuits being main oil circuits 6, 7, and the charge circuit 9 supplying the pressure oil into the closed circuit 8. It has the relief valve 12 regulating a maximum pressure in the closed circuit 8, and the neutral valve 13 capable of blocking leaking following oil pressure rising of the high pressure side oil circuit while allowing leaking to the charge circuit 9 from the high pressure side oil circuit being one of the pair of main oil circuits 6, 7, is integrally incorporated in the relief valve 12.