Flow visualization of flowing particles around a tube of various types of tube arrangements in a moving bed was studied using X-ray video films to obtain a relation between particles behavior and local heat-transfer coefficients. A stagnant part of solid particles was observed on the tube in the case of a staggered arrangement. This part did not appear in the case of the single tube and the single row of tubes. The measured local hear-transfer coefficients around a tube was decreased in this stagnant part Furthermore, influences of different tribe arrangements both on flow patterns of particles and on local heat-transfer coefficients between tubes and bed were examined.