Seatbelt buckle apparatus

A seat belt buckle device that fixes a tongue plate provided at a seat belt, comprising

• an outer case into which the tongue plate is inserted;
• a latch member rotatably mounted within the outer case and configured to rotate in response to the insertion of the tongue plate into the outer case and latches the tongue plate;
• a release button slideably mounted within the outer case and configured to release latching of the tongue plate by the latch member by sliding into the outer case;
• and
• a counterweight mounted within the outer case and configured to be rotated by a force received from the release button while resisting sliding of the release button, wherein
• the counterweight has:
• a first rotating shaft rotatably supporting the counterweight with respect to the outer case;
• and
• a second rotating shaft that is engaged with a bearing groove formed in the release button and configured to receive the force that rotates the counterweight due to the sliding of the release button, and
• the second rotating shaft having a recessed portion in an outer circumferential surface of the second rotating shaft, the recessed portion being configured to come into contact with the bearing groove of the release button when the release button slides into the outer case.