To provide concrete blocks for a greened parking lot with turf or the like, the concrete blocks being arranged so that wheels of a vehicle are put thereon and the root zone ratio of turf or the like can be improved.

A concrete block 1 forms a portal cross section having an upper slab 12 and both side walls 13 and 13. The side walls 13 and 13 have legs 14 and 14 projecting in the outer direction. The side walls 13 and 13 have window holes 15 and 15 in communication with an interior space 16, and the upper slab 12 also has holes 17 and 17 in communication with the interior space 16.