To provide a technique for easily producing a biomass composite material in which a dispersed phase originated from the biomass is minutely and homogeneously distributed.

The biomass composite material is produced by blending a secondary resin with a concentrate product of a biomass resin in which a biomass originated component is blended in a higher ratio than the biomass composite material. A primary resin constituting the concentrate product comprises a polyolefin-based resin produced by a single site catalyst as a main component and has a melting point measured by DSC (Differential Scanning Calorimetry) in a predetermined range, and the relation T1T2 is satisfied when T1 represents a melting peak temperature of the primary resin by DSC measurement and T2 represents a melting peak temperature of the blended secondary resin.