An image encoding device 1 of the present disclosure includes a neighboring pixel non-reference predictor 11 configured to generate a predicted image by a predetermined neighboring pixel non-reference prediction for each pixel signal of an original image in a block unit, a filter processor 12 configured to perform a low-pass filter process on a prediction signal located at a boundary of a block of the predicted image by using a decoded neighboring signal neighboring to the predicted image under a predetermined control, a prediction residual signal generator 55 configured to generate a prediction residual signal of the block unit by using the predicted image, an orthogonal transformer 14 configured to perform an orthogonal transformation process on the prediction residual signal of the block unit under the predetermined control, and an orthogonal transformation selection controller 25 configured to control the filter processor 12 and the orthogonal transformer 14 and generate a predetermined transformation type identification signal. An image decoding device 5 of the present disclosure performs a decoding process based on a transformation type identification signal at the time of the predetermined neighboring pixel non-reference prediction.