1. A defect inspection apparatus for inspecting a sheet-like inspection object using a photographed image of the sheet-like inspection object, the photographed image being input from a photographing apparatus, the defect inspection apparatus comprising: at least one processor configured to divide the photographed image of the sheet-like inspection object into blocks each of which has a size of a first predetermined number of pixels by a second predetermined number of pixels; calculate, for each block, a longitudinal variance based on pixel values in a longitudinal direction in the block and a lateral variance based on pixel values in a lateral direction in the block; determine, for each block, whether the block is a defect candidate using the longitudinal variance and the lateral variance as sheet-like inspection object defect determination evaluation values; and determine that the sheet-like inspection object has a first type of defect based on a first number of consecutive blocks in the photographed image determined as the defect candidates exceeding a length threshold, and that the sheet-like inspection object has a second type of defect based on a second number of consecutive blocks in the photographed image determined as the defect candidates exceeding an area threshold, wherein the first type of defect corresponds to a stripe defect and the second type of defect corresponds to an unevenness defect.