An engine noise control apparatus which is capable of effectively reducing or waveform-reshaping a wide range of engine noise. The apparatus has an engine rotating speed sensor (5) for detecting an engine rotating speed and a waveform generator circuit (46) for converting a rotation pulse signal to a periodic signal having a frequency which is a predetermined multiple of the detected engine rotating speed. The output of an air flow meter (3) is passed through a bandpass filter (41) and a rectifier circuit (42) to generate a control signal which is an average value of alternating current components of the output. A CPU (44), with reference to a map previously stored in a memory (45), modifies the phase and amplitude of the periodic signal with respect to an engine rotation reference signal based on the rotation pulse signal and the control signal, and outputs the modified signal as driving signals to operate speakers (6A, 6B) disposed in an intake tube and an exhaust tube for reducing noise.