<p>The circuit opening operation section (202) of an embodiment of switchgear operation mechanism comprises: a circuit opening electromagnetic solenoid (60) having a fitting structure that is provided with a step; and a solenoid spacer (62) for adjusting the distance between a circuit opening trigger mechanism (201) and the circuit opening electromagnetic solenoid (60). The circuit opening solenoid (60) has: a solenoid housing fixed in position by way of the solenoid spacer (62); a plunger (60a); and a stopper (63) fitted to the solenoid housing so as to limit the sliding motion of the plunger in the plunger returning direction when the coil is not supplied with electric power. The limiting position of the stopper (63) is adjustable.</p>
