In the invention providing a board-to-board coaxial connector, a contact portion 17 is formed in an internal conductor housing portion 12 of a plug body 9 into which a receptacle center conductor 7 is to be inserted. The contact portion has: a stationary contact piece portion 10b which is perpendicularly bent from a solder connecting portion 10a of a plug internal conductor 10 to extend in the axial direction of the connector; and movable contact piece portions 10c which are continuous to the stationary contact piece portion, which are juxtaposed in a circumferential direction of the connector, and which extend in the axial direction of the connector.