Today, the use of anycast address is quite limited. One of the reasons is because there is no routing protocol providing a global anycasting service. In this paper we design and implement a new anycast routing protocol called PIA-SM (Protocol Independent Anycast - Sparse Mode). We focus on PIM-SM (Protocol Independent Multicast - Sparse Mode), which is one of multicast routing protocols available now, to develop an anycast routing protocol because anycast and multicast have many similar properties. We modified PIM-SM based on differences between multicast and anycast. We next describe technical issues to be solved on the implementation of PIA-SM. We also show some experimental results to demonstrate PIA-SM, and verify that PIA-SM enables routers to forward an anycast packet to an appropriate node of multiple candidate nodes.