Lock mechanism for electric retractable seat for vehicle

A lock mechanism for an electric retractable seat for a vehicle, includes a seat cushion frame (13), a seat back frame (17), a guide groove (28), a latch (42) including an engagement opening portion (42a), a slide member (16) disengaging from the engagement opening portion (42a) when the latch (42) is in an unlocked position, engaging with the engagement opening portion (42a) during a movement of the seat cushion frame (13) to the seating position, and being locked between the guide groove (28) and the engagement opening portion (42a) when the latch (42) is in a locked position, a pawl (43) for restricting the latch (42) from pivoting when the pawl (43) is in a restricted position, and allowing the latch (42) to pivot when the pawl (43) is in a released position, a releasing member (47) for rotating the pawl (43).