Vehicle seat belt device

A vehicle seat belt device, comprising:

• a buckle device configured to be disposed on a first side in a width direction of a vehicle seat;
• a lap belt configured to have a first end portion locked at the vehicle seat or a vehicle body on a second side in the width direction of the vehicle seat, and to restrain a waist part of an occupant who sits on the vehicle seat when a tongue attached to a second end portion is connected to an upper end portion of the buckle device;
• an anchor part configured to be provided at the vehicle seat or the vehicle body on the first side in the width direction of the vehicle seat, and to displace a lower end portion of the buckle device, which is connected to the anchor part so as to be rotatable around an axis line along a vehicle width direction, to a vehicle front side by being deformed by a load applied from the lap belt to the buckle device at a time of collision of a vehicle;
• and
• a buckle rotation mechanism configured to include a guide part that is provided at the vehicle seat or the vehicle body on a vehicle downward side of the buckle device and inclined downward toward the vehicle front side, and a pull-in part that connects the guide part and an upper portion of the buckle device and is slidable along the guide part, and to rotate the buckle device to the vehicle front side and the vehicle downward side due to the displacement.