A medical stopcock 1 includes a housing 2 and a cock 3. The housing 2 includes a cylindrical the body section 6 formed with a through-hole 6a, an upstream port section 7, a downstream port section 8, and a port section 9 for a side tube. The port section 9 for a side tube includes a first communication hole 13 and a second communication hole 14 having an opening area smaller than that of the first communication hole 13. The cock 3 includes a cylindrical section 31. The cylindrical section 31 is formed with a first flow path groove 33 communicating with the upstream port section 7 and the first communication hole 13, and a second flow path groove 14 communicating with the second communication hole 14 and the downstream port section 8.
