A phased array antenna comprising: a front plate on which a flow path through which coolant flows is formed; a plurality of blocks including a plurality of slices that includes a plurality of transmitters and a circuit board configured tc distribute a power to the transmitters to control operation and to control a passing phase of a high-frequency signal, and a bus board to distribute a power, a control signal, and a high-frequency signal to the plurality of slices, the blocks being held on a first face of the front plate; a plurality of power sources to supply power to the blocks, the power sources being held on the first face of the front plate; an antenna element layer in which a plurality of antenna elements are arrayed, the antenna element layer being held on a second face on the back of the first face of the front plate; and a high-frequency signal wiring layer including high-frequency signal wiring through which a high-frequency signal to the plurality of antenna elements passes, the high-frequency signal wiring layer being held on the second face of the front plate, wherein the front plate has a through hole, and the transmitters include a connector electrically connected to the high-frequency signal wiring via the through hole, characterized in that the high-frequency signal wiring is shifted in an in-plane direction of the front plate in the high-frequency signal wiring layer, a pitch (P 1) between the antenna elements is shorter than both a pitch (P 2) of the slices of adjacent blocks and a pitch (P 3) of the slices within the block 6, and the pitch (P 2) between the plurality of slices of the adjacent blocks is independent of the pitch (P 1) between the plurality of antenna elements. a front plate on which a flow path through which coolant flows is formed; a plurality of blocks including a plurality of slices that includes a plurality of transmitters and a circuit board configured tc distribute a power to the transmitters to control operation and to control a passing phase of a high-frequency signal, and a bus board to distribute a power, a control signal, and a high-frequency signal to the plurality of slices, the blocks being held on a first face of the front plate; a plurality of slices that includes a plurality of transmitters and a circuit board configured tc distribute a power to the transmitters to control operation and to control a passing phase of a high-frequency signal, and a bus board to distribute a power, a control signal, and a high-frequency signal to the plurality of slices, the blocks being held on a first face of the front plate; a plurality of power sources to supply power to the blocks, the power sources being held on the first face of the front plate; an antenna element layer in which a plurality of antenna elements are arrayed, the antenna element layer being held on a second face on the back of the first face of the front plate; and a high-frequency signal wiring layer including high-frequency signal wiring through which a high-frequency signal to the plurality of antenna elements passes, the high-frequency signal wiring layer being held on the second face of the front plate, wherein the front plate has a through hole, and the transmitters include a connector electrically connected to the high-frequency signal wiring via the through hole, characterized in that the high-frequency signal wiring is shifted in an in-plane direction of the front plate in the high-frequency signal wiring layer, a pitch (P 1) between the antenna elements is shorter than both a pitch (P 2) of the slices of adjacent blocks and a pitch (P 3) of the slices within the block 6, and the pitch (P 2) between the plurality of slices of the adjacent blocks is independent of the pitch (P 1) between the plurality of antenna elements.