A coaxial connector plug includes a first outer conductor with a cylinder shape extending in a first direction, a first center conductor that has a cylinder shape extending in the first direction and is provided inside the first outer conductor, and an insulation member that fixes the first center conductor to the first outer conductor. In the coaxial connector plug, a communication section to cause the inside and the outside of the first center conductor to communicate with each other is provided in an end portion of the first center conductor on one side in the first direction. A width of the communication section in a second direction orthogonal to the first direction becomes larger as it progresses from the one side toward the other side of the first direction, and the insulation member penetrates from the outside to the inside of the first center conductor through the communication section.