Provided are: a method and a kit for producing a biological specimen clear, which enable the clearing within a short time and by which a wide variety of biological specimens can be cleared； and a method and a kit for preserving a cleared biological specimen. A method for producing a cleared biological specimen, comprising steps as mentioned in items (A) to (C). (A) Step (1) of treating a material to be cleared with a fixing solution that is an aqueous solution containing paraformaldehyde or the like, a nonionic surfactant (at a concentration of 1% or more) and an alkali and optionally containing a buffering agent to produce the material that is cleared is involved. (B) Step (2) of treating the material that is produced in step (1) or a material to be cleared which is produced by a conventional fixing method with a clearing accelerator solution that is an aqueous solution containing a nonionic surfactant (at a concentration of 1% or more) and an alkali to produce the material that is cleared is involved. (C) Step (3) of treating the material produced in step (1) or (2) with a preservation solution that is an aqueous solution containing a nonionic surfactant (at a concentration of 1% or more) and a polyhydric alcohol to produce the material that is cleared is involved. A kit which can be used in the method.
