To provide a brake mechanism with a simple structure which can apply a braking force corresponding to the residual amount of a single-dose packaging paper to a single-dose packaging paper roll fitted on a medicine packaging apparatus.

The single-dose packaging paper roll is provided with a paper pipe and the single-dose packaging paper rolled around the paper pipe. The brake mechanism comprises a contacting part, which comes in contact with at least one lateral side of the rolled single-dose packaging paper when the single-dose packaging paper roll is fitted on the medicine packaging apparatus, makes frictional contact with the lateral side of the rolled single-dose packaging paper when the paper pipe is revolved on its axis, and is arranged in such a way that the area of the contact between the contacting part and the lateral side of the rolled single-dose packaging paper is proportional to the residual amount of the single-dose packaging paper.