Porous photocatalytic TiO2 thin films were fabricated by the leaching technique, followed by aerosol deposition. Mixed powders of TiO2 and β-tricalcium phosphate (TCP) were aerosol deposited at room temperature for the initial fabrication of composite films. After the β-TCP phases were leached out from the composite films in a diluted HCl aqueous solution for 24 h, porous TiO2 films remained on the substrate. To fabricate these porous films, the β-TCP content was varied from 10 to 45 wt% and submicrometer-sized pores were formed after leaching. The porous TiO2 films showed strong initial photocatalytic activities due to the adsorption effect of the pores and the enlarged surface area.