A photoacoustic microscope objective lens unit includes: an objective lens which irradiates a sample with excitation light L a photoacoustic wave detection unit which detects a photoacoustic wave U generated from the sample and a photoacoustic wave guide system. The photoacoustic wave guide system includes: a photoacoustic wave separation member and an acoustic lens that is disposed between the photoacoustic wave separation member and the sample and has a focus position that substantially matches with a focus position of the objective lens. The acoustic lens is obtained by cementing a main acoustic lens and a correction acoustic lens to each other. The main acoustic lens and the correction acoustic lens satisfy predetermined Conditional Expressions.