A subdural sensor (10, 10A, 10B, 10C, 10E, 10F) that is to be arranged in a subdural space and acquires biological information about the brain, comprising: a substrate (100, 100a, 100b, 100d, 100e, 100f) formed of a flexible material; and at least one type of sensor part (110, 120, 130) mounted on the substrate (100, 100a, 100b, 100d, 100e, 100f), wherein the substrate (100, 100a, 100b, 100d, 100e, 100f) has an elongated shape as a whole, wherein the substrate (100, 100a, 100b, 100d, 100e, 100f) includes a sensor area (101, 101a, 101b, 101e, 101f) in which the at least one type of sensor part (110, 120, 130) is mounted and a wiring pattern connected to the at least one type of sensor part (110, 120, 130) is formed, wherein a tip part of the sensor area (101, 101a, 101b, 101e, 101f) has a planar shape that curves convexly toward an outer periphery, the substrate (100, 100a, 100b, 100d, 100e, 100f) further includes: a wiring area (102, 102a, 102b, 102d, 102e, 102f) contiguous with the sensor area (101, 101a, 101b, 101e, 101f) on one end thereof, the wiring pattern extending in the wiring area (102, 102a, 102b, 102d, 102e, 102f); and a connector area (103, 103b, 103c) contiguous with the other end of the wiring area (102, 102a, 102b, 102d, 102e, 102f), the connector area (103, 103b, 103c) being an area on which a connector to be connected to the wiring pattern extending from the wiring area (102, 102a, 102b, 102d, 102e, 102f) is mounted, characterized in that the tip part of the sensor area (101, 101a, 101b, 101e, 101f) has a side shape that curves toward a first surface, the first surface being on the side of a dura mater when the subdural sensor (10, 10A, 10B, 10C, 10E, 10F) is inserted into the subdural space. a substrate (100, 100a, 100b, 100d, 100e, 100f) formed of a flexible material; and at least one type of sensor part (110, 120, 130) mounted on the substrate (100, 100a, 100b, 100d, 100e, 100f), wherein the substrate (100, 100a, 100b, 100d, 100e, 100f) has an elongated shape as a whole, wherein the substrate (100, 100a, 100b, 100d, 100e, 100f) includes a sensor area (101, 101a, 101b, 101e, 101f) in which the at least one type of sensor part (110, 120, 130) is mounted and a wiring pattern connected to the at least one type of sensor part (110, 120, 130) is formed, wherein a tip part of the sensor area (101, 101a, 101b, 101e, 101f) has a planar shape that curves convexly toward an outer periphery, the substrate (100, 100a, 100b, 100d, 100e, 100f) further includes: a wiring area (102, 102a, 102b, 102d, 102e, 102f) contiguous with the sensor area (101, 101a, 101b, 101e, 101f) on one end thereof, the wiring pattern extending in the wiring area (102, 102a, 102b, 102d, 102e, 102f); and a connector area (103, 103b, 103c) contiguous with the other end of the wiring area (102, 102a, 102b, 102d, 102e, 102f), the connector area (103, 103b, 103c) being an area on which a connector to be connected to the wiring pattern extending from the wiring area (102, 102a, 102b, 102d, 102e, 102f) is mounted, characterized in that the tip part of the sensor area (101, 101a, 101b, 101e, 101f) has a side shape that curves toward a first surface, the first surface being on the side of a dura mater when the subdural sensor (10, 10A, 10B, 10C, 10E, 10F) is inserted into the subdural space. a wiring area (102, 102a, 102b, 102d, 102e, 102f) contiguous with the sensor area (101, 101a, 101b, 101e, 101f) on one end thereof, the wiring pattern extending in the wiring area (102, 102a, 102b, 102d, 102e, 102f); and a connector area (103, 103b, 103c) contiguous with the other end of the wiring area (102, 102a, 102b, 102d, 102e, 102f), the connector area (103, 103b, 103c) being an area on which a connector to be connected to the wiring pattern extending from the wiring area (102, 102a, 102b, 102d, 102e, 102f) is mounted, characterized in that the tip part of the sensor area (101, 101a, 101b, 101e, 101f) has a side shape that curves toward a first surface, the first surface being on the side of a dura mater when the subdural sensor (10, 10A, 10B, 10C, 10E, 10F) is inserted into the subdural space.