Lifetime diagnostic device and power conversion device

A life diagnostic device (1) is provided with a Vce amplifier (12), a Vee amplifier (13), and a life diagnostic unit (21). A Vce amplifier (12) measures a voltage (Vce) between a collector main terminal (6) connected to a collector electrode of a semiconductor element (5) mounted on a semiconductor device (2) and an emitter main terminal (8) connected to an emitter electrode of the semiconductor element (5). A Vee amplifier (13) measures a voltage Vee between an emitter main terminal (8) and an emitter reference terminal (9) connected to the emitter electrode. The lifetime diagnosis unit (21) diagnoses the lifetime of the semiconductor device (2) using a correlation value between the change over time of the voltage (Vce) and the change over time of the voltage (Vee). 寿命诊断装置(1)具备Vce放大器(12)、Vee放大器(13)以及寿命诊断部(21)。Vce放大器(12)测量和搭载于半导体装置(2)的半导体元件(5)的集电极电极连接的集电极主端子(6)与和半导体元件(5)的发射极电极连接的发射极主端子(8)之间的电压(Vce)。Vee放大器(13)测量发射极主端子(8)与和发射极电极连接的发射极参考端子(9)之间的电压Vee。寿命诊断部(21)使用电压Vce的经时变化和电压Vee的经时变化的相关值，诊断半导体装置(2)的寿命。