An image forming apparatus includes a first conveying path, a second conveying path, a detector, a conveyance guide member and an interlock mechanism. The first conveying path communicates the second conveying path through which a sheet supplied from a supply part is conveyed. The detector detects whether or not the sheet is present in the first conveying path. The conveyance guide member composes the second conveying path and one end part thereof is pivotally supported so as to be able to open/close the second conveying path. The interlock mechanism interlocks the detector with the opening/closing operation of the conveyance guide member. The detector detects the opening/closing operation of the conveyance guide member.