It is an object of the present invention to provide a trehalose compound having high immunopotentiating activity and low toxicity. The trehalose compound is represented by formula (1). (In the formula, X and X" each represents a phenyl, a naphtyl, R1-CHR1- (wherein R1 and R2 each represents a C7-C21 alkyl group or the like) or the like and n and n" each independently represents an integer of 0-3). The compound exhibits a high activating effect on macrophages and neutrophils. [Formula 1]