We studied physical properties of matter in 24 544 filaments ranging from 30 to 100 Mpc in length, identified in the Sloan Digital Sky Survey. We stacked the Comptonization y map produced by the Planck Collaboration around the filaments, excluding the resolved galaxy groups and clusters above a mass of ∼3 × 10 13   M ⊙ . We detected the thermal Sunyaev-Zel’dovich signal for the first time at a significance of 4.4 σ in filamentary structures on such a large scale. We also stacked the Planck cosmic microwave background lensing convergence map in the same manner and detected the lensing signal at a significance of 8.1 σ . To estimate physical properties of the matter, we considered an isothermal cylindrical filament model with a density distribution following a β -model ( β = 2/3). Assuming that the gas distribution follows the dark matter distribution, we estimate that the central gas and matter overdensity δ and gas temperature T e are δ = 19.0 −12.1 +27.3 and T e = 1.4 −0.4 +0.4 × 10 6 K, which results in a measured baryon fraction of 0.080 −0.051 +0.116 × Ω b .