1. A moving image encoding apparatus for performing encoding using inter prediction between frames, comprising: a processor; and a memory storing a program which, when executed by the processor, causes the apparatus to: generate a predicted image for prediction encoding processing; divide an original image into blocks each having a predetermined number of pixels, and perform orthogonal transformation and quantization on a difference between an encoding target image and the predicted image for each of the blocks; generate an encoded stream by encoding the transformation result; generate a locally decoded image by performing inverse quantization and inverse orthogonal transformation on the transformation result; calculate a PSNR (Peak Signal-to-Noise Ratio) from the original image and the locally decoded image; calculate a first filter intensity based on the calculated PSNR; correct the first filter intensity based on a conspicuity value of block noise, wherein the conspicuity value is determined by comparing a boundary difference value between adjacent boundary pixels and a peripheral difference value between adjacent pixels other than the boundary pixels of the locally decoded image and another locally decoded image adjacent to the locally decoded image, and a second filter intensity estimated based on encoding information obtained from a result of the prediction encoding processing and pattern information of the adjacent boundary pixels; and perform a deblocking filter processing on the locally decoded image using the corrected filter intensity.