A code amount estimation device includes a code amount estimation unit configured to estimate a first target code amount on the basis of a first code amount estimation area in first image information and a code amount estimation model for estimating the first target code amount for each first code amount estimation area using the first code amount estimation area and multiple first quantization parameters determined in advance, and the code amount estimation model is a model generated by associating a second code amount estimation area in second image information, multiple second quantization parameters, and a second target code amount for each second code amount estimation area when coding is performed with respective values of multiple second quantization parameters with each other.