Abstract: A temperature sensing device for test cylinder is provided. The device includes a heat-transfer member that is covered with a top cover and is then set along with the top cover in a holding case to form a temperature sensing unit of the device. The heat-transfer member is provided at an upper side at a position best for correctly sensing temperature with an upper recess for receiving a sensing element therein, and at a lower side with channels for receiving conductors of a cable externally connected to and extended into the holding case. The upper recess of the heat-transfer member is filled with resin to enclose the sensing element therein and adhesively connect to a bottom surface of the top cover. The temperature-sensing unit has a concave top corresponding to a test cylinder to enable close and fit contact of the test cylinder with the top cover. The entire temperature sensing unit and the test cylinder are hold together by positioning them into a fixing unit of the device.