A connector mateable with a mating connector along a predetermined direction. The mating connector comprises a ground member and a mating signal terminal. The ground member has a ground contacted portion and a locked portion. The connector comprises a first portion, a second portion and a signal terminal. The first portion has a lock portion and a lock spring portion. The lock portion is brought into contact with the ground contacted portion in a process where the connector and the mating connector are mated with each other. The lock portion locks the locked portion under a state where the connector is mated with the mating connector. The signal terminal has a signal contact portion. The signal contact portion is to be brought into contact with the mating signal terminal.