To provide an opening/closing device for sheet or net which can perform opening and closing of the sheet or net in a plurality of places at one time using a single device, allows simplification of the structure and saving the working costs and equipment costs, and can enhance the performance of the opening/closing works to a great extent.

One end of a sheet 17 or net spread along the framework of a vinyl house is wound on pipe 8, which is coupled with a power transmission device 1, and this is rotated in the normal or reverse direction so that the sheet 17 or net is wound up or unwound. In this opening/closing device for the sheet 17 or net of vinyl house, one or more bevel gear mechanisms 5 are installed on a rotary shaft 4 driven by the power transmission device 1, and the pipe 8 is rotatably coupled with each bevel gear mechanism 5.