The invention provides a solid-state image pickup device for an auto-focus and a camera for an auto-focus in which focusing precision is improved. The device has first and second linear sensor pairs (for example, 2-1, 2-2) each having a linear sensor for a base portion with a plurality of pixels and a linear sensor for a reference portion with a plurality of pixels in order to perform a focal point detection of a TTL passive-type phase detection system. The first and second linear sensor pairs have the same pixel pitch, the first and second linear sensor pairs are neighboring in parallel and are arranged so as to be relatively deviated in the arranging direction of the linear sensors, and a signal output to detect the focal point is executed by using both of the first and second linear sensor pairs.