A picture quality improving apparatus which is low in cost and small in circuit scale has a vertical low-pass filter (LPF) for extracting a vertical low-frequency component from an input luminance signal, a horizontal LPF for extracting a horizontal low-frequency component from the output signal from the vertical LPF, a subtractor for subtracting the output signal from the horizontal LPF from the luminance signal which has been compensated for the delay, a gain adjusting circuit for adjusting the gain of an edge signal produced by the subtractor, and an adder for adding the edge signal whose gain has been adjusted to the delay-compensated luminance signal. Each of the vertical LPF and the horizontal LPF comprises an FIR (finite impulse response) filter and an IIR (infinite impulse response) filter which are connected in cascade or parallel to each other.