A sensor device, comprising: a flexible sheet (10, 30, 110) comprising a reference electrode (14, 34, 114) which is formed on a lower surface of the sheet (10, 30, 110) in the Z-axis direction; a base plate (11b, 31b, 111b), wherein the base plate (11b, 31b, 111b) includes a first electrode (12, 32, 112) and a second electrode (13, 33, 113); a support layer (11a, 31a, 111a) comprising first structures (15, 35, 115) with a first height such that a space portion (17, 37, 117) having an interval with a first height in the Z-axis direction is formed between the base plate (11b, 31b, 111b) and the reference electrode (14, 34, 114) and second structures (16, 36, 116) with a second height shorter than the first height arranged in the space portion (17, 37, 117) in the Z-axis direction above both the first electrode (12, 32, 112) and the second electrode (13, 37, 113), and the space portion being formed between the second structures (16, 36, 116) and the reference electrode (14, 34, 114); wherein the material forming the second structures (16, 36, 116) has a specific dielectric constant higher than that of air present in the space portion (17, 37, 117); and the first electrode (12, 32, 112) and the second electrode (13, 33, 113) constitute a capacitive element, and a change in capacitance between the first electrode (12, 32, 112) and the second electrode (13, 33, 113) is detected when the reference electrode (14, 34, 114) is brought closer to the base plate (11b, 31b, 111b), wherein the first electrode (12, 112) is an X electrode and the second electrode (13, 113) is a Y electrode; and the first electrode (12, 112) and the second electrode (13, 113) cross each other at positions where the second structures (16, 116) are arranged, or wherein the first electrode and the second electrode are both X electrodes arranged side by side on an upper surface of the base plate. a flexible sheet (10, 30, 110) comprising a reference electrode (14, 34, 114) which is formed on a lower surface of the sheet (10, 30, 110) in the Z-axis direction; a base plate (11b, 31b, 111b), wherein the base plate (11b, 31b, 111b) includes a first electrode (12, 32, 112) and a second electrode (13, 33, 113); a support layer (11a, 31a, 111a) comprising first structures (15, 35, 115) with a first height such that a space portion (17, 37, 117) having an interval with a first height in the Z-axis direction is formed between the base plate (11b, 31b, 111b) and the reference electrode (14, 34, 114) and second structures (16, 36, 116) with a second height shorter than the first height arranged in the space portion (17, 37, 117) in the Z-axis direction above both the first electrode (12, 32, 112) and the second electrode (13, 37, 113), and the space portion being formed between the second structures (16, 36, 116) and the reference electrode (14, 34, 114); wherein the material forming the second structures (16, 36, 116) has a specific dielectric constant higher than that of air present in the space portion (17, 37, 117); and the first electrode (12, 32, 112) and the second electrode (13, 33, 113) constitute a capacitive element, and a change in capacitance between the first electrode (12, 32, 112) and the second electrode (13, 33, 113) is detected when the reference electrode (14, 34, 114) is brought closer to the base plate (11b, 31b, 111b), wherein the first electrode (12, 112) is an X electrode and the second electrode (13, 113) is a Y electrode; and the first electrode (12, 112) and the second electrode (13, 113) cross each other at positions where the second structures (16, 116) are arranged, or wherein the first electrode and the second electrode are both X electrodes arranged side by side on an upper surface of the base plate.