Membrane potential change detection device and membrane potential change detection method

The disclosed membrane potential change detection device (1) is provided with a reflection interference measurement light source (106), a holding unit (103) which holds a transparent member (102a) on which a cell (101) is mounted, a reflection interference detection camera (110) which is irradiated from the reflection interference measurement light source (106) and generates reflection interference images by forming images from the light reflected from the cell (101) through the transparent member (102a), and an analysis unit (202) which calculates from the reflection interference images a parameter (dI) relating to the adhesion of the cell (101) and the transparent member (102a) and detects change in the membrane potential of the cell (101) on the basis of changes in said parameter (dI).