According to one embodiment, a radiotherapy information generation apparatus includes a region specific unit and a planning estimation unit. The region specific unit is configured to specify at least one area defined with respect to a tumor by analysis processing of diagnostic image data. The planning estimation unit is configured to display estimation information of planned dose values calculated based on the area and expected dose values of a radiation. Further, according to another embodiment, a radiotherapy information generation method includes specifying at least one area defined with respect to a tumor by analysis processing of diagnostic image data; and displaying estimation information of planned dose values calculated based on the area and expected dose values of a radiation.