A scalable video encoding method of performing encoding by predicting an upper-layer signal using an immediately-lower-layer signal, the upper-layer signal having a higher spatial resolution than the immediately-lower-layer signal, the method being characterized by comprising: a step (S3, S21) that computes a first weighting coefficient for each image area of a predetermined unit size in a search for estimating a motion between an encoding target image area located in the upper layer of an encoding target frame and a reference image area located in the upper layer of a reference frame, the reference frame being a different frame than the encoding target frame, where the first weighting coefficient is computed based on a brightness variation between an image area, which belongs to an immediately-lower layer and has the same spatial position as the encoding target image area, and the reference image area; a step (S3, S22, S26) that performs a motion estimation using a signal which is obtained by correcting a decoded signal of the reference image area by the first weighting coefficient and functions as an estimated signal in the motion estimation, so as to compute a motion vector; a step (S4, S32) that computes a second weighting coefficient based on a brightness variation between a reference image area which is located in the upper layer of the reference frame and is indicated by the computed motion vector and the image area which belongs to the immediately-lower layer of the upper layer of the encoding target frame and has the same spatial position as the encoding target image area; and a motion compensation step (S4, S33) that determines a signal, which is obtained by correcting a decoded signal of the reference image area indicated by the motion vector by using the second weighting coefficient, to be a compensated signal in motion compensation, which functions as a predicted signal of the encoding target image area. a step (S3, S21) that computes a first weighting coefficient for each image area of a predetermined unit size in a search for estimating a motion between an encoding target image area located in the upper layer of an encoding target frame and a reference image area located in the upper layer of a reference frame, the reference frame being a different frame than the encoding target frame, where the first weighting coefficient is computed based on a brightness variation between an image area, which belongs to an immediately-lower layer and has the same spatial position as the encoding target image area, and the reference image area; a step (S3, S22, S26) that performs a motion estimation using a signal which is obtained by correcting a decoded signal of the reference image area by the first weighting coefficient and functions as an estimated signal in the motion estimation, so as to compute a motion vector; a step (S4, S32) that computes a second weighting coefficient based on a brightness variation between a reference image area which is located in the upper layer of the reference frame and is indicated by the computed motion vector and the image area which belongs to the immediately-lower layer of the upper layer of the encoding target frame and has the same spatial position as the encoding target image area; and a motion compensation step (S4, S33) that determines a signal, which is obtained by correcting a decoded signal of the reference image area indicated by the motion vector by using the second weighting coefficient, to be a compensated signal in motion compensation, which functions as a predicted signal of the encoding target image area.