To provide a porous road paving with excellent permeability and water retentivity as a concrete molding using only waste concrete or the like as aggregate for the purpose of reclaiming a large amount of waste concrete produced in a large amount.

Cement of not less than 17 wt.% (in dry weight) nor more than 20 wt.% (in dry weight) is added to waste concrete grains obtained by crushing waste concrete, in which the content of grains with grain sizes of not more than 0.3 mm are 5 wt.% or less and the content of grains with grain sizes of 5 mm or more are 3 wt.% or less. Water of not less than 15% nor more than 25% is added to the weight of these solids and both high vibration and high compression are used to obtain a molding through an immediate demolding process. Thereafter, the molding is cured in a steam-saturated atmosphere for 24 hours or more. The molded concrete paving or a road boundary block is obtained having a permeability of 1.05×10-2 cm/sec or more and being excellent in bending strength, compression strength and water retentivity.