A radar device, comprising: a housing that includes an aperture on a front surface, defining a front direction as a direction of transmission of an electromagnetic wave normal to the aperture; a circuit board that is disposed in the housing such that a board surface is disposed along the front direction; an antenna unit that includes two or more antenna elements being arrayed in a region of the circuit board along a direction transverse to the front direction, and that is configured to transmit the electromagnetic wave to outside of the housing through the aperture and to receive a reflected wave of the electromagnetic wave; and a dielectric lens integrally formed with the housing and that is disposed in the aperture of the housing to extend along a direction in which the two or more antenna elements are arrayed, and that has a semi-cylindrical shape or a parabolic-cylindrical shape projecting in the front direction, characterized in that the housing and the dielectric lens are formed from the same resin material, and wherein based on an upward direction and a downward direction orthogonal to an extending direction of the circuit board , the antenna unit is disposed at a position deviated from an optical axis of the dielectric lens in the upward direction in the housing , the antenna unit being configured to transmit the electromagnetic wave in a transmitting direction that is tilted downwards with respect to the extending direction of the circuit board , or the antenna unit is disposed at a position deviated from an optical axis of the dielectric lens in the downward direction in the housing , the antenna unit being configured to transmit the electromagnetic wave in a transmitting direction that is tilted upwards with respect to the extending direction of the circuit board . a housing that includes an aperture on a front surface, defining a front direction as a direction of transmission of an electromagnetic wave normal to the aperture; a circuit board that is disposed in the housing such that a board surface is disposed along the front direction; an antenna unit that includes two or more antenna elements being arrayed in a region of the circuit board along a direction transverse to the front direction, and that is configured to transmit the electromagnetic wave to outside of the housing through the aperture and to receive a reflected wave of the electromagnetic wave; and a dielectric lens integrally formed with the housing and that is disposed in the aperture of the housing to extend along a direction in which the two or more antenna elements are arrayed, and that has a semi-cylindrical shape or a parabolic-cylindrical shape projecting in the front direction, characterized in that the housing and the dielectric lens are formed from the same resin material, and wherein based on an upward direction and a downward direction orthogonal to an extending direction of the circuit board , the antenna unit is disposed at a position deviated from an optical axis of the dielectric lens in the upward direction in the housing , the antenna unit being configured to transmit the electromagnetic wave in a transmitting direction that is tilted downwards with respect to the extending direction of the circuit board , or the antenna unit is disposed at a position deviated from an optical axis of the dielectric lens in the downward direction in the housing , the antenna unit being configured to transmit the electromagnetic wave in a transmitting direction that is tilted upwards with respect to the extending direction of the circuit board . <EOS>