A solid-state imaging device includes a semiconductor region of p-type; a buried region of n-type, configured to serve as a photodiode together with the semiconductor region; a extraction region of n-type, configured to extract charges generated by the photodiode from the buried region, having higher impurity concentration than the buried region; a read-out region of n-type, configured to accumulate charges, which are transferred from the buried region having higher impurity concentration than the buried region; and a potential gradient changing mechanism, configured to control a potential of the channel, and to change a potential gradient of a potential profile from the buried region to the read-out region and a potential gradient of a potential profile from the buried region to the extraction region, so as to control the transferring/extraction of charges.