A sheet includes a pseudo-sheet structure including a plurality of linear-bodies with a volume resistivity R of from 1.0×10−7 Ωcm to 1.0×10−1 extending in one direction, aligned parallel to one another, and spaced apart from one another, satisfies the relation: L/D≥3, wherein D represents the diameter of the linear-bodies, and L represents the spacing between adjacent ones of the linear-bodies, and also satisfies the relation: (D2/R)×(1/L)≥0.003, wherein D represents the diameter of the linear-bodies, L represents the spacing between adjacent ones of the linear-bodies, R represents the volume resistivity of the linear-bodies, and D and L are in units of cm. A heating element and a heating device each include the sheet.