Clamp portions (24) are provided on two sides in a vertical direction of each of flanges (21) and (22) of a filter (10) which is a fluid apparatus having a directionality, and guide grooves (28) and (29) are formed mutually different in shape between the other two sides of the flanges (21) and (22) and a coupling head (14). On the other hand, clamp portions (34) are provided on four sides of each of flanges (31) and (32) of a regulator (11) which is a fluid apparatus having no directionality, and clamp grooves (35) are formed between the clamp portions (34) and a coupling head (18). A connector (13) includes tongue portions (51) engaged with the clamp portions (24) and (34), guide protrusions (53) inserted into the guide groove (28) and the clamp groove (35), and guide protrusions (54) inserted into the guide groove (29) and the clamp groove (35), and the regulator (11) is coupled to the filter (10) in any posture.