An modular plug includes a plug main body that can be inserted into and removed from a connector; an engaging claw configured to engage the plug main body with the connector; and an operations lever configured to turn off engagement of the plug main body and the connector by the engaging claw; wherein a lock turning-off member is provided at the plug main body so that the lock turning-off member can be slid in inserting and removing directions; an inclination surface of the lock turning-off member is formed in a position facing the operations lever; and the inclination surface operates the operation lever accompanying sliding in the inserting direction of the lock-turning off member so that the engagement of the engaging claw and the connector is turned off.