A connector with booster mechanism includes a housing, an operation lever rotatably mounted on the housing and including an arm portion, a drive gear integrally rotatably provided on the operation lever, a speed-reduction member rotatably mounted on the housing, and a slider. The drive gear is coaxial with a rotation center shaft and disposed at a position different from the arm portion in an axial direction of the rotation center shaft. The speed-reduction member includes a large-diameter gear to be meshed with the drive gear and a small-diameter gear having a smaller diameter than the large-diameter gear and coaxial with the large-diameter gear. The slider includes a rack to be meshed with the small-diameter gear and is mounted on the housing movably in a direction intersecting a connecting direction to a mating connector.