The electronic component tester includes: a socket configured to supply power to connection terminals for operating an electronic component; an electronic component mount member on which the electronic component is to be mounted; and a temperature adjusting member which is configured to come into contact with the electronic component mount member to keep the electronic component at a predetermined temperature. The electronic component mount member includes a heat transfer plate on which the electronic component is to be mounted and which is configured to come into contact with the temperature adjusting member, and an electronic component cover for covering the electronic component. The heat transfer plate includes through holes.