Abstract: A sensor for a currentmeter includes a supporting member which is provided to support a pair of transmitter/receiver units which rotate around an axis that is not parallel to (i.e.-intersects) a transmission path of supersonic waves which propagate between the units. Sing-around signals which are transmitted correspond to each rotating position of the supporting member. Since only one pair of transmitter/receiver units is required, current turbulence caused by the supporting member is reduced so that a highly precise measurement of the current flowing between the pair of transmitter/receiver units may be obtained.