This invention provides a platelet-rich plasma separator, which can carry out the separation of a platelet-rich plasma with a small number of gamma radiation sterilized instruments, and a platelet-rich plasma separation method. The platelet-rich plasma separator comprises a first syringe (10) and a second syringe (11). The first syringe (10) comprises a first syringe cylinder (13) provided with a first port (12) on which a blood collection needle can be mounted, a first cap (14) detachable from the first port (12), a first gasket (15) for sealing the first syringe cylinder (13) fluid-tightly, which first gasket (15) is reciprocated within the first syringe cylinder (13), and a first plunger (16) provided detachably on the first gasket (15). The second syringe (11) comprises a first hollow needle (30), which can be passed through the first gasket (15), a second syringe cylinder (32) having a second port (31) on which the first hollow needle (30) can be mounted, a second cap (33) detachable from the second port (32), a second gasket (34) for sealing the second syringe cylinder (32) liquid-tightly, which second gasket (34) is reciprocated within the second syringe cylinder (32), and a second plunger (35) provided detachably on the second gasket (34).