Object search is a fundamental ability for a service robot to provide higher level services. We focus on object search in an environment with limited free space to place objects and constrained viewpoints to observe the environment, such as a shelf or a cupboard. We propose an object search planner based on A* search algorithm with tree node sampling. The proposed approach also combines visual and arm manipulation search. In other words, the robot searches occluded target object by either repositioning one of the accessible object with its arm or moving its platform to view the environment from a different pose. We evaluate the proposed approach with experiment performed by real robot in the scenario which objects may occlude or block access to one another.