A three-dimensional data encoding method of encoding three-dimensional points includes: calculating a new predicted value as a predicted value, using attribute information items of one or more second three-dimensional points neighboring a first three-dimensional point, and assigning the predicted value to at least one prediction mode among two or more prediction modes, the new predicted value being used for calculating an attribute information item of the first three-dimensional point; selecting one prediction mode from the two or more prediction modes; calculating a prediction residual which is a difference between the attribute information item of the first three-dimensional point and the predicted value of the one prediction mode selected; and generating a bitstream including the one prediction mode and the prediction residual.