PURPOSE: To suppress the production of a code quantity by not coding a high frequency component of an orthogonal transformation coefficient depending on a mean value and a variance of a prediction error.

CONSTITUTION: A picture signal of a current frame and a reproduced picture of a preceding frame are compared and a motion vector detection section 2 calculates a motion vector and a motion compensation prediction control signal and a motion compensation prediction section 4 applies motion compensation prediction to a reproduced picture of the preceding frame. A coding method discrimination section 5 discriminates whether a coded block is subject to inter-frame coding or an in-frame coding. A prediction error calculation section 7 takes a difference between an original picture signal of a coded block and a prediction signal to calculate a prediction error. An orthogonal transformation section 9 implements orthogonal transformation and a coefficient and replacement section 10 rearranges the orthogonal transformation coefficients in the order of frequencies. A mean value and variance calculation section 12 calculates the mean value and the variance of the total sum of difference absolute values calculated by the prediction error calculation section 7. A coding coefficient selection section 13 selects a low frequency component of the orthogonal transformation coefficient coded by the mean value and variance and a high frequency component not coded.