A connector, comprising: a housing fitted into a mating side housing; a locking arm including a locking portion; and a slider, wherein the locking arm is connected to the housing and extends toward a rear end and along a fitting direction into the mating side housing, wherein the locking arm is configured to be restored after bending in a lock release direction and the locking portion is configured to be engaged with an engagement portion of the mating side housing to lock the mating side housing and the housing, when the housing is being fitted into the mating side housing, wherein the slider is slidably attached to the housing between a main locking position and a temporary locking position deviating from the main locking position, the main locking position being a position where the locking arm is pressed at a pressing portion on a bending end side, and wherein the slider is configured to be moved from the temporary locking position to the main locking position, so that the rear end of the locking arm is abutted on an abutting surface of a bending regulation portion of the slider, and the bending of the locking arm toward the housing is regulated, characterized in that at least one of the slider and the locking arm includes a push-back inclined surface inclined downward toward a front in the fitting direction, wherein when the slider at the temporary locking position is unintentionally pushed toward the main locking position before the housing is fitted into the mating side housing, and the rear end of the locking arm bending toward the housing is in contact with the push-back inclined surface of the slider, force is applied to the slider, and the slider is pushed back in a direction away from the main locking position. a housing fitted into a mating side housing; a locking arm including a locking portion; and a slider, wherein the locking arm is connected to the housing and extends toward a rear end and along a fitting direction into the mating side housing, wherein the locking arm is configured to be restored after bending in a lock release direction and the locking portion is configured to be engaged with an engagement portion of the mating side housing to lock the mating side housing and the housing, when the housing is being fitted into the mating side housing, wherein the slider is slidably attached to the housing between a main locking position and a temporary locking position deviating from the main locking position, the main locking position being a position where the locking arm is pressed at a pressing portion on a bending end side, and wherein the slider is configured to be moved from the temporary locking position to the main locking position, so that the rear end of the locking arm is abutted on an abutting surface of a bending regulation portion of the slider, and the bending of the locking arm toward the housing is regulated, characterized in that at least one of the slider and the locking arm includes a push-back inclined surface inclined downward toward a front in the fitting direction, wherein when the slider at the temporary locking position is unintentionally pushed toward the main locking position before the housing is fitted into the mating side housing, and the rear end of the locking arm bending toward the housing is in contact with the push-back inclined surface of the slider, force is applied to the slider, and the slider is pushed back in a direction away from the main locking position.