A safety device with a push-push type latch device latching and releasing a movable body to a main body by a push operation, has a circulation cam groove provided in the movable body; a responding member provided in the main body, and having a pin for tracing the circulation cam groove and a balancer; and an urging member for urging the responding member. When the responding member receives a load, the responding member turns and the circulation cam groove allows the pin to irreversibly move from a reciprocation groove portion to a latch groove portion through a latching guide groove portion. When the movable body retained in the fixed position receives the push operation, the circulation cam groove allows the pin to move from the latch groove portion to the reciprocation groove portion through the returning guide groove portion, thereby releasing the movable body from the fixed position.