We have performed photoacoustic micro-imaging using a microphone detection technique. A microcomputer controlled photoacoustic imaging system is developed. A sample on a sensitive photoacoustic cell is scanned mechanically and photoacoustic signals generated by a focused laser beam are detected with a condenser microphone and a lock-in amplifier. The magnitude and the phase images of photoacoustic signal are displayed on a TV monitor. To obtain a clearer sub-surface image, digital image enhancement techniques are employed. Spatial resolution of the present photoacoustic microscope is 15μm. Some subsurface images and a power transistor image are presented.