[Problem] To provide a portable terminal assessment device and a portable terminal assessment method capable of assessing the proper price which can spur demand for a consumer to replace a portable terminal. [Solution] Provided is a portable terminal assessment device that assesses a buyback price of a portable terminal 10, the assessment device comprising: a terminal information storage unit that stores terminal-specific information specific to the portable terminal 10, for each identifier specific to the portable terminal 10 to be assessed, terminal state information which relates to the operation state of the portable terminal 10, and additional information of the portable terminal 10 additionally input based on a visual confirmation; a market price database 302D that stores a market price of the portable terminal 10 for each terminal-specific information piece; a subtraction rate table that stores a subtraction rate, which is a ratio, in respect to a market price, of an amount of money obtained by subtrac