Hydroxyapatite/collagen (HAp/Col) composite scaffold with unidirectionally elongated pores (scaffold-U) was fabricated by the unidirectional solidification with ice growth and subsequent freeze-dry process. The pore architecture in the composite was evaluated by using scanning electron microscopy (SEM) and micro computed tomography (micro-CT) with a high resolution. The SEM observation showed that the scaffold-U had unidirectional pores elongated along the vertical direction (i.e. ice growth direction), however the horizontal cross-section showed quite different pore morphology: spindle-shaped pores with random direction. The 3-D micro-CT image of the scaffold-U simultaneously showed the microstructure of the unidirectionally elongated pore and the cross-sectional pore, indicating that the interconnected micropores were successfully fabricated along the ice growth direction. The micro-CT is a powerful tool for the visualization of 3-D pore structure.