We investigated the effects of differences in tree species and their appearance, weight, texture, smell, and surface properties on the selection of wooden blocks by parents who purchase building blocks for their babies and infants. The wooden blocks (45-mm cubes using materials with straight grain on two surfaces) used in the study were made of sugi (Cryptomeria japonica), hinoki (Chamaecyparis obtusa), hiba (Thujopsis dolabrata var. hondai), and buna (Fagus crenata). The surface was polished with #240 abrasive paper and all sides were processed to 3mm radius. In addition, wooden blocks made of sugi and hinoki materials with floating processing on the surface were used. A total of seven types of blocks, including commercially available plastic blocks, were used for the survey. The survey target was 26 guardians of children. The main findings were: 1) the criteria for selection of blocks given to children were higher considering the children’s play, characteristics of materials, and price; 2) the selection order differed depending on the presented stimulus, sugi and hinoki wood blocks were selected as gifts for children instead of buna, hiba, and plastic blocks; 3) floating processing blocks were selected as blocks for children because they increase playability and do not irritate the skin; 4) considering their safety and weight, sugi wood blocks polished with #240 abrasive paper were selected as being suitable for children to hit, drop, and throw; and 5) considering their stability and safety, sugi and hinoki wood blocks polished with #240 abrasive paper were selected as being suitable for children to stack.