A honeycomb structure body having joining material layers of a stress relaxing function and joining strength equivalent to those of joining material layers of a conventional honeycomb structure body, and having an excellent heat shock resistance. A honeycomb structure body includes a plurality of honeycomb segments and joining material layers having a plurality of pores and joining the plurality of honeycomb segments in a state where the honeycomb segments are arranged adjacent to each other so that side surfaces of the honeycomb segments face each other. A ratio of the number of pores having a value of 1.2 or less which is obtained by dividing a maximum diameter of each of the pores by a minimum diameter of the each of the pores is 60% or more of the number of all the pores of each of the joining material layers.