A sliding door suspension device for supporting a door that is displaced in a prescribed opening/closing direction by a drive force from an opening/closing drive mechanism, the sliding door suspension device comprising: a driving-side member which is displaceable in the opening/closing direction when the drive force is imparted from the opening/closing drive mechanism; a hanger which is configured so as to be displaceable in the opening/closing direction in conjunction with a displacement of the driving-side member and which supports the door; an elastic member which allows relative displacements of the driving-side member and the hanger in the opening/closing direction by elastically deforming in accordance with a load in the opening/closing direction that acts between the driving-side member and the hanger; pressed door rollers (52, 72) which are arranged between a pair of upper and lower rails (43, 44) of the sliding door suspension device; movement conversion mechanisms being configured to convert a movement in which the driving-side member and the hanger are relatively displaced in the opening/closing direction, into a movement in which the pressed door rollers (52, 72) are pressed against the upper rail, wherein the movement conversion mechanisms include linking mechanisms (53, 73), each of the linking mechanisms (53, 73) includes a first spindle, a first linking member which is capable of swinging around the first spindle in accordance with relative movements of the driving-side member and the hanger in the opening/closing direction, the swinging of the first linking member causing said movement of the pressed door rollers (52,72), each pressed door roller (52,72) is supported by a second linking member which is coupled to the first linking member and the sliding door suspension device further comprises a coupling member for coupling the linking mechanisms (53,73) and the driving side member to each other, and configured so as to be displaced in conjunction with the driving-side member and configured so as to relatively displace the driving-side member and the second linking member in the opening/closing direction in accordance with an elastic deformation of the elastic member, and the coupling member is inserted into a fitting hole section (31a,32a) formed on the driving-side member and is slidable in the opening/closing direction with respect to the fitting hole section (31a, 32a). a driving-side member which is displaceable in the opening/closing direction when the drive force is imparted from the opening/closing drive mechanism; a hanger which is configured so as to be displaceable in the opening/closing direction in conjunction with a displacement of the driving-side member and which supports the door; an elastic member which allows relative displacements of the driving-side member and the hanger in the opening/closing direction by elastically deforming in accordance with a load in the opening/closing direction that acts between the driving-side member and the hanger; pressed door rollers (52, 72) which are arranged between a pair of upper and lower rails (43, 44) of the sliding door suspension device; movement conversion mechanisms being configured to convert a movement in which the driving-side member and the hanger are relatively displaced in the opening/closing direction, into a movement in which the pressed door rollers (52, 72) are pressed against the upper rail, wherein the movement conversion mechanisms include linking mechanisms (53, 73), each of the linking mechanisms (53, 73) includes a first spindle, a first linking member which is capable of swinging around the first spindle in accordance with relative movements of the driving-side member and the hanger in the opening/closing direction, the swinging of the first linking member causing said movement of the pressed door rollers (52,72), each pressed door roller (52,72) is supported by a second linking member which is coupled to the first linking member and the sliding door suspension device further comprises a coupling member for coupling the linking mechanisms (53,73) and the driving side member to each other, and configured so as to be displaced in conjunction with the driving-side member and configured so as to relatively displace the driving-side member and the second linking member in the opening/closing direction in accordance with an elastic deformation of the elastic member, and the coupling member is inserted into a fitting hole section (31a,32a) formed on the driving-side member and is slidable in the opening/closing direction with respect to the fitting hole section (31a, 32a).