An image forming apparatus 100 includes a cassette fitting portion 1 which is provided in the main body of the image forming apparatus 100 and a paper feed cassette 30 which includes a sheet storage portion S. In the cassette fitting portion 1, a lift plate 50 is provided which raises and lowers a sheet 18. In the cassette base 31 of the sheet storage portion S, an opening portion 31a is formed in a position opposite the lift plate 50. The lift plate 50 is arranged selectively either in a lowered position in which the lift plate 50 is arranged below the cassette base 31 or in a raised position in which the lift plate 50 is protruded above the cassette base 31 through the opening portion 31a so as to allow the sheet 18 to be fed.