A power supply circuit breaker device (1) is configured to include: a fixed-side connector device (2) provided partway along a power supply circuit (D); a movable-side connector device (3) which engages/disengages with the fixed-side connector device (2) to turn ON/OFF the power supply circuit (D); and a rotary connection mechanism (4) for engagement/disengagement between the connector devices and turning ON/OFF the power supply circuit. The rotary connection mechanism (4) is configured such that, in the engagement/disengagement between the connector devices and the turning ON/OFF of the power supply circuit, the movable-side connector device (3) is made linearly movable along an engagement direction (P), and the movable-side connector device (3) is made rotatably movable in a direction (Q) around a rotation axis parallel to the engagement direction (P).