An RFID reader-writer comprising: an antenna configured to transmit and receive electromagnetic waves; a reader configured to read out at least information stored in an RF tag via the electromagnetic waves transmitted and received by the antenna; a housing in which the antenna and the reader are housed, wherein the housing includes external surfaces (30, 31, 32, 34, 40, 42, 45, 46) which are exposed outward; the external surfaces include a first surface, a second surface facing the first surface back to back, and a plurality of side surfaces (21, 22, 23, 24) each being continuous to both the first and second surfaces, the first surface providing a front of the RFID reader-writer, the second surface providing a rear of the RFID reader-writer; characterized in that the first surface includes a part formed as a reading surface enabling the electromagnetic waves to be transmitted and received therethrough, a finger-grip groove, and one of a pair of grip surfaces (32, 42), the finger-grip groove being located between the reading surface and the one surface and adjacent to both the reading surface and the one surface; the second surface includes a placing surface, a thumb-attaching groove, and the other of the pair of grip surfaces (32, 42), the other surface being faced with the one surface back to back, the thumb-attaching groove being located between the placing surface and the other surface and adjacent to both the placing surface and the other surface, the placing surface being provided for stationary use of the RFID reader-writer; the pair of grip surfaces (32, 42) and one of the side surfaces (21, 22, 23, 24) configure a handgrip used by a user for gripping the RFID reader-writer with a thumb and other fingers, other than the thumb, of the user; and the antenna is disposed inside the housing so as to be faced with the reading surface, such that the antenna enables transmitting and receiving the electromagnetic waves through the reading surface. an antenna configured to transmit and receive electromagnetic waves; a reader configured to read out at least information stored in an RF tag via the electromagnetic waves transmitted and received by the antenna; a housing in which the antenna and the reader are housed, wherein the housing includes external surfaces (30, 31, 32, 34, 40, 42, 45, 46) which are exposed outward; the external surfaces include a first surface, a second surface facing the first surface back to back, and a plurality of side surfaces (21, 22, 23, 24) each being continuous to both the first and second surfaces, the first surface providing a front of the RFID reader-writer, the second surface providing a rear of the RFID reader-writer; characterized in that the first surface includes a part formed as a reading surface enabling the electromagnetic waves to be transmitted and received therethrough, a finger-grip groove, and one of a pair of grip surfaces (32, 42), the finger-grip groove being located between the reading surface and the one surface and adjacent to both the reading surface and the one surface; the second surface includes a placing surface, a thumb-attaching groove, and the other of the pair of grip surfaces (32, 42), the other surface being faced with the one surface back to back, the thumb-attaching groove being located between the placing surface and the other surface and adjacent to both the placing surface and the other surface, the placing surface being provided for stationary use of the RFID reader-writer; the pair of grip surfaces (32, 42) and one of the side surfaces (21, 22, 23, 24) configure a handgrip used by a user for gripping the RFID reader-writer with a thumb and other fingers, other than the thumb, of the user; and the antenna is disposed inside the housing so as to be faced with the reading surface, such that the antenna enables transmitting and receiving the electromagnetic waves through the reading surface.