[26], the method of fabricating bone scaffolds is divided into 3D printing and traditional methods. 3D printing techniques are classified with direct methods such as stereolithography (SLA), selective layer sintering (SLS), and ink-jet printing as well as indirect methods, for example, wax printing. A paper adopting the wax printing method was recently reported. [PERSON] and [PERSON] [27] fabricated honeycomb porous bone scaffolds composed of chitosan/hydroxyapatite (CS/HA) composites with pores uniformly distributed using a wax mold that was printed on a three-dimensional (3D) printer. The scaffolds exhibited higher porosity and compressive strength than other porous CS/HA scaffolds manufactured via other production methods. The mechanical properties of the scaffolds varied for different fabrication processes, even with the same materials. [PERSON] et al. [28] observed the porosity and mechanical properties of 3D scaffolds, which depend on the processing method of the bio-ink materials. The materials were composed of hydroxyapatite (HA) and, according to the processing method, the porous and mechanical properties were measured differently. It was found that the initial materials influenced the fabrication process, by affecting the shrinkage after sintering, which is related to both the porosity and the compressive strength. Indeed, bone scaffolds made with 3D printers have shown low mechanical properties compared with those made with traditional methods. Meanwhile, traditional methods have been developed in a variety of ways, including gas forming, phase separation, and solvent casting [26]. [PERSON] et al. created HA scaffolds using the freeze-gel casting method, which combines freeze casting and gel casting [29]. The HA scaffold had high mechanical properties indicating a higher compressive stress than 35 MPa, but unfortunately the porosity was significantly lower. [PERSON] et al. [21] also adopted freeze-gel casting methods for manufacturing biphasic calcium phosphate (BCP) scaffolds. They obtained similar results, with very high mechanical strength but a somewhat lower porosity. Therefore, research should continue to try and overcome the difficulties of fabricating bone scaffolds similar to cancellous bone having a porosity of 50 to 90% or more than 75% and the compressive strength of 1-12 MPa [7; 30]. In this study, artificial bone scaffolds with good porous and mechanical properties similar to cancellous bone were fabricated. The structural changes occurring inside the scaffold during the fabrication process were observed in order to examine the origin of the good mechanical properties of high-porosity scaffolds. A freeze-gel casting method for high compressive strength [21; 29; 31] was used to prepare highly porous HA scaffolds. The main material was artificial HA, which is similar to the component of cancellous bone, and the microstructure of the scaffolds was controlled by adding different amounts of the porogen poly (methyl methacrylate) (PMMA) [19]. In this process, tert-butyl alcohol (TBA) was selected as the freezing solvent, which created columnar pore channels by removing itself during freeze-drying [32; 33]. The fabricated porous HA scaffolds were characterized with regard to their crystalline phase, microstructure, and physical and mechanical properties. Then, the observed structure and tendency of the variation of the properties were analyzed for determining why highly porous scaffolds have higher compressive strength than less porous scaffolds.