A safety bed provided by detachably arranged on a generally standard or other bed or infant's crib a gate rotatably carried by anchor means inserted under the mattress for frictional retention, making possible instant conversion of a standard or other bed to a safety bed as well as instant reconversion thereof. The gate is secured by suitable locking means in elevated position, inhibiting passage of the occupant's body from the bed. Upon release of the lock the gate may be lowered, permitting such passage. Various alternative forms of locks are disclosed, one form permitting disengagement of the gate from the anchor means. Also, various means are disclosed for attachment to the anchor means to reduce wear on the bedding by shifting of the anchor.