A magnetic type device for detecting the thickness of a sheet-type medium comprising: a fixing frame configured to support and install the following components; a reference shaft having two ends installed onto the fixing frame through bearings, and receiving a power as an input power source for a sheet-type medium, with a reference roller being fixedly fitted on the reference shaft: a detection shaft having two ends fixedly installed onto the fixing frame, the detection shaft being provided thereon with at least one floating support frame which has one end capable of rotating freely about the detection shaft, and a detection roller being freely rotatable and provided on a free end of the floating support frame, and a signal generator being fixedly provided at the free end of the floating support frame on a side opposite to the detection roller, with the detection roller being arranged in elastic contact with the reference roller; an elastic pressing plate having one end fixed to the fixing frame and the other end forming a free end and applying a pressing force to the floating support frame in a direction towards the reference roller, and a signal inductor arranged spaced from the floating support frame and corresponding to the signal generator, characterized in that the elastic pressing plate is composed of at least stacked two elastic sheets and the elastic sheets have one end relatively fixed and the other end forming a freely stacked state, the number of the floating support frames is twelve groups, and the elastic pressing plate is a strip-shaped elastic plate, and twelve elastic pressing bars corresponding to the floating support frames are extended from the elastic plate. a fixing frame configured to support and install the following components; a reference shaft having two ends installed onto the fixing frame through bearings, and receiving a power as an input power source for a sheet-type medium, with a reference roller being fixedly fitted on the reference shaft: a detection shaft having two ends fixedly installed onto the fixing frame, the detection shaft being provided thereon with at least one floating support frame which has one end capable of rotating freely about the detection shaft, and a detection roller being freely rotatable and provided on a free end of the floating support frame, and a signal generator being fixedly provided at the free end of the floating support frame on a side opposite to the detection roller, with the detection roller being arranged in elastic contact with the reference roller; an elastic pressing plate having one end fixed to the fixing frame and the other end forming a free end and applying a pressing force to the floating support frame in a direction towards the reference roller, and a signal inductor arranged spaced from the floating support frame and corresponding to the signal generator, characterized in that the elastic pressing plate is composed of at least stacked two elastic sheets and the elastic sheets have one end relatively fixed and the other end forming a freely stacked state, the number of the floating support frames is twelve groups, and the elastic pressing plate is a strip-shaped elastic plate, and twelve elastic pressing bars corresponding to the floating support frames are extended from the elastic plate. a detection shaft having two ends fixedly installed onto the fixing frame, the detection shaft being provided thereon with at least one floating support frame which has one end capable of rotating freely about the detection shaft, and a detection roller being freely rotatable and provided on a free end of the floating support frame, and a signal generator being fixedly provided at the free end of the floating support frame on a side opposite to the detection roller, with the detection roller being arranged in elastic contact with the reference roller; an elastic pressing plate having one end fixed to the fixing frame and the other end forming a free end and applying a pressing force to the floating support frame in a direction towards the reference roller, and a signal inductor arranged spaced from the floating support frame and corresponding to the signal generator, characterized in that the elastic pressing plate is composed of at least stacked two elastic sheets and the elastic sheets have one end relatively fixed and the other end forming a freely stacked state, the number of the floating support frames is twelve groups, and the elastic pressing plate is a strip-shaped elastic plate, and twelve elastic pressing bars corresponding to the floating support frames are extended from the elastic plate.