Why checkbox is not binding value of object field (Angular 4)

I want to bind field value in current object and switch checkbox depend on it value.

My checkbox:

<label class="checkbox-inline checbox-switch switch-success">
<input
  #livingRoom
  type="checkbox"
  name="livingRoom"
  id="livingRoom"
  [checked]="showDefaultTypeRoom.isExistLivingRoom"
/>
<span></span>
</label>

I change showDefaultTypeRoom object and isExistLivingRoom but my checkbox is not switching depend on isExistLivingRoom value.

How fix it?