Inspecting device and inspecting method

An inspecting device comprising:

• an irradiation part for irradiating an inspecting target with each of pump light and probe light having the same pulse period;
• a detection part for detecting an electromagnetic wave generated from said inspecting target by irradiating said inspecting target with said probe light;
• a measurement delay part for delaying the time of arrival of said probe light at said inspecting target relatively to said pump light;
• and
• a reverse bias voltage applying part for applying a reverse bias voltage to said inspecting target, wherein
• said irradiation part includes a scanning mechanism to scan with said probe light a scanned and observed area which is larger than an irradiated area being irradiated with said pump light in said inspecting target, an area which is not irradiated with said pump light being also observed in addition to the irradiated area, and
• a diameter of a spot of said probe light is smaller than a diameter of a spot of said pump light, and
• the reverse bias voltage applied by said reverse bias voltage applying part is variable.