The auto-sampler for chromatographs includes a needle for sampling configured to move while a tip end thereof faces vertically downward; a switching valve having a plurality of ports to which channels constituting a chromatograph are connected, the switching valve switching between port connecting conditions to switch between channel configurations; and an injection port including an opening at an upper surface thereof through which a tip end of the needle is inserted to make the needle fluidically communicate with a pipe connected to one port of the switching valve, and a needle seal configured to get into contact with an outer circumferential surface of the tip end portion to make the needle fluidically communicate with the pipe in a liquid-tight manner when the tip end of the needle is inserted through the opening.