A male connector (1; 2) with a lock mechanism comprising: a bar-shaped male member for insertion into a female connector (100; 200); and a lock mechanism for maintaining a state in which the male member is inserted into the female connector, wherein the lock mechanism includes: a hood that is arranged so as to surround a periphery of the male member and is for insertion of the female connector; and a lock lever having a cantilever support structure capable of elastic displacement; and wherein: the lock lever is arranged with a free end thereof on a tip side of the male member and with a fixed end thereof on a base end side of the male member, the lock lever includes a claw for engaging with the female connector, an operation arm protrudes from a face of the lock lever on a side opposite to the male member, and extends toward the fixed end side, the lock lever has an elastic portion that is capable of elastic deformation, and when a pressing force in a direction approaching the male member is applied to a tip of the operation arm, the lock lever undergoes elastic deformation such that the claw moves away from the male member; characterised in that: the lock lever is a single lock lever, the lock lever is shaped as a thin plate with its lengthwise direction being approximately parallel to a central axis of the male member, one end portion of the lock lever in the lengthwise direction is the free end, and the other end portion of the lock lever in the lengthwise direction is the fixed end, a base end of the operation arm to which the lock lever is connected is provided at a position on the free end side relative to the fixed end of the lock lever, and the elastic portion is between the fixed end of the lock lever and the base end of the operation arm. a bar-shaped male member for insertion into a female connector (100; 200); and a lock mechanism for maintaining a state in which the male member is inserted into the female connector, a hood that is arranged so as to surround a periphery of the male member and is for insertion of the female connector; and a lock lever having a cantilever support structure capable of elastic displacement; and wherein: the lock lever is arranged with a free end thereof on a tip side of the male member and with a fixed end thereof on a base end side of the male member, the lock lever includes a claw for engaging with the female connector, an operation arm protrudes from a face of the lock lever on a side opposite to the male member, and extends toward the fixed end side, the lock lever has an elastic portion that is capable of elastic deformation, and when a pressing force in a direction approaching the male member is applied to a tip of the operation arm, the lock lever undergoes elastic deformation such that the claw moves away from the male member; the lock lever is arranged with a free end thereof on a tip side of the male member and with a fixed end thereof on a base end side of the male member, the lock lever includes a claw for engaging with the female connector, an operation arm protrudes from a face of the lock lever on a side opposite to the male member, and extends toward the fixed end side, the lock lever has an elastic portion that is capable of elastic deformation, and when a pressing force in a direction approaching the male member is applied to a tip of the operation arm, the lock lever undergoes elastic deformation such that the claw moves away from the male member; the lock lever is a single lock lever, the lock lever is shaped as a thin plate with its lengthwise direction being approximately parallel to a central axis of the male member, one end portion of the lock lever in the lengthwise direction is the free end, and the other end portion of the lock lever in the lengthwise direction is the fixed end, a base end of the operation arm to which the lock lever is connected is provided at a position on the free end side relative to the fixed end of the lock lever, and the elastic portion is between the fixed end of the lock lever and the base end of the operation arm.