A seat bag mounting structure for mounting a seat bag on an occupant seat of a saddle riding type vehicle, comprising: a mounting member (21, 21A) disposed in a lateral direction on the occupant seat, the mounting member (21, 21A) being attached, at right and left ends thereof, to the occupant seat such that the seat bag is mounted on the mounting member (21, 21A), wherein the mounting member (21, 21A) comprises: a connector main unit; a first side connecting belt (22L, 22R) connected to a first side of the connector main unit in the length direction thereof, and a second side connecting belt removably connected to a second side of the connector main unit in the length direction thereof, the second side connecting belt including a loop portion at a distal end thereof, the connector main unit includes: a second side insertion hole formed on the second side in the length direction thereof for allowing the distal end of the second side connecting belt to be passed therethrough; a first side mounting hole formed on a first side of the second side insertion hole in the length direction thereof, a laterally-extending lock rod disposed at a central side of the first side mounting hole in the length direction thereof, the lock rod having a free lateral end; and a gap provided between the free lateral end and the first side mounting hole, for allowing the loop portion to be put into the gap so as to be locked relative to the lock rod, characterized by a pad, which is disposed between the connector main unit and an outer surface of a passenger seat in the mounted state, is placed along an inner surface of the connector main unit and is formed to be greater than the connector main unit and has a first end side tapered to have a decreasing width toward an end portion that is formed to be substantially identical in width to the first side connecting belt (22L, 22R); wherein the pad is overlapped with an inner surface of the first side connecting belt (22L, 22R) and an end portion of the pad is fixed to the first side connecting belt (22L, 22R) by the sewing portion. a mounting member (21, 21A) disposed in a lateral direction on the occupant seat, the mounting member (21, 21A) being attached, at right and left ends thereof, to the occupant seat such that the seat bag is mounted on the mounting member (21, 21A), wherein the mounting member (21, 21A) comprises: a connector main unit; a first side connecting belt (22L, 22R) connected to a first side of the connector main unit in the length direction thereof, and a second side connecting belt removably connected to a second side of the connector main unit in the length direction thereof, the second side connecting belt including a loop portion at a distal end thereof, a connector main unit; a first side connecting belt (22L, 22R) connected to a first side of the connector main unit in the length direction thereof, and a second side connecting belt removably connected to a second side of the connector main unit in the length direction thereof, the second side connecting belt including a loop portion at a distal end thereof, the connector main unit includes: a second side insertion hole formed on the second side in the length direction thereof for allowing the distal end of the second side connecting belt to be passed therethrough; a first side mounting hole formed on a first side of the second side insertion hole in the length direction thereof, a laterally-extending lock rod disposed at a central side of the first side mounting hole in the length direction thereof, the lock rod having a free lateral end; and a gap provided between the free lateral end and the first side mounting hole, for allowing the loop portion to be put into the gap so as to be locked relative to the lock rod, characterized by a second side insertion hole formed on the second side in the length direction thereof for allowing the distal end of the second side connecting belt to be passed therethrough; a first side mounting hole formed on a first side of the second side insertion hole in the length direction thereof, a laterally-extending lock rod disposed at a central side of the first side mounting hole in the length direction thereof, the lock rod having a free lateral end; and a gap provided between the free lateral end and the first side mounting hole, for allowing the loop portion to be put into the gap so as to be locked relative to the lock rod, characterized by a pad, which is disposed between the connector main unit and an outer surface of a passenger seat in the mounted state, is placed along an inner surface of the connector main unit and is formed to be greater than the connector main unit and has a first end side tapered to have a decreasing width toward an end portion that is formed to be substantially identical in width to the first side connecting belt (22L, 22R); wherein the pad is overlapped with an inner surface of the first side connecting belt (22L, 22R) and an end portion of the pad is fixed to the first side connecting belt (22L, 22R) by the sewing portion.