A three-dimensional printing apparatus that forms a three-dimensional object using cross-sectional shapes of the object includes a controller that is configured or programmed to include a dividing unit that divides a cross-sectional shape into a plurality of blocks, a shape determining unit that determines whether one of the blocks has a predetermined shape and defines the block having the predetermined shape as a characteristic block, a count determining unit that determines whether the proportion of the number of the characteristic blocks to the total number of the blocks is equal to or greater than a predetermined proportion, and a light application unit that sets the energy of light from a light source to a first energy or to a second energy being lower than the first energy depending on the proportion, when applying the light to a photocurable resin in a region corresponding to the characteristic blocks.