Rocky protoplanetary dust is thought to have low sticking properties and thus suffer from fragmentation, bouncing, and drift during collisional growth. However, the organic coatings have been found on chondritic porous interplanetary dust particles collected in the stratosphere and may affect the sticking properties of rocky protoplanetary dust (Flynn et al., 2013). On the other hand, a formose-type reaction is one of the potential synthetic reactions of meteoritic and cometary organic matter including amino acids, sugars, and insoluble organic matter (Cody et al., 2011; Furukawa et al., 2021). Therefore, we measured the cohesive force of the organic matter formed by the reaction using a centrifugal method (Nagaashi et al., 2018; 2021). The organic matter was prepared thermochemically from formaldehyde, glycolaldehyde, and ammonia under the same condition as previously reported by Furukawa et al. (2021). Water-soluble and volatile components were removed from the products prior to the cohesive force measurement. The cohesive force of the products measured at ambient temperature and pressure was 0.1?0.2 µN, which was larger than those of carbonaceous chondrite fragments measured at ambient temperature and pressure (0.03?0.1 µN: Nagaashi et al., 2021). This may be due to differences in surface structure or material, as electron microscopy images show that the synthetic organic matter is composed of micron- to submicron-sized particles, while the meteorite fragments have surface structures on the submicron scale or smaller.