To inhibit the sliding of a building material effectively by forming hard granular body groups on one surface or both surfaces of a sheet.

The non-slip sheet 40 is constituted by installing a large number of hard granular bodies 42 on both surfaces of a sheet 41, and the hard granular bodies 42 are configured of a metallic piece, etc., as a frictional resistance member for increasing frictional resistance force towards the surface direction between opposed flanges 11, 21. The sheet 40 is positioned between the flange 11 in the upper section of a first steel material 10 and the flange 21 in the lower section of a second steel material 20, both steel materials 10, 20 are abutted, a vice 30 is set at the superposing places of the flanges 11, 21, and a bolt 32 is clamped. Since the clamping force of the vice 30 is applied to the sheet 40 interposed between the flanges 11, 21, a hard granular body 42 group is intruded to the base materials of the flanges 11, 21, flange 11, 21 themselves are joined so as to be mutually engaged, the clamping force of the vice 30 and the frictional resistance force of the sheet 40 resist against force directed in parallel with the flanges 11, 21, and movement in the direction is constrained.