In a sheet conveying mechanism, a first bulging space and a second bulging space are provided on a downstream side and an upstream side, respectively, of a conveying path. The second bulging space has a length L1 along the conveying path. The conveying path between the first and second bunging spaces is defined to have a length L2. The lengths L1 and L2 are set to satisfy a predetermined relationship with a frequency of noise propagating through the conveying path. The sheet conveying mechanism can inexpensively reduce noise generated inside the conveying path during sheet conveyance without hindering the conveyance of the sheet.