A method for manufacturing a high-strength cement cured product constituted by: mixing and kneading cement with at least water and water-reducing agent; putting the cement kneaded mixture (5) into a vacuum device and removing air and dehydrating by vacuum evacuation; forming an impermeable coating layer (7) on the surface of the cement kneaded mixture (5) contained in a container inside the vacuum device (1) and then exposing the cement kneaded mixture (5) to atmospheric pressure; and then curing the cement kneaded mixture (5). This enables it to be hardened while having a reduced air amount. Thereby, a high-strength cement cured product having high compressive strength can be obtained.