Particle analysis device

A particle analysis device comprising

• a flow cell through which a sample containing particles flows,
• a light source that irradiates light to the particles in the flow cell,
• a photodetector that detects secondary light from the particles,
• an arithmetic circuit that calculates an autocorrelation function from a light intensity signal output by the photodetector and analyzes the particles contained in the sample using the autocorrelation function,
• an optical system unit including a casing that houses the flow cell and the light source,
• a control unit provided separately from the optical system unit and including the photodetector and the arithmetic circuit, wherein the photodetector and the arithmetic circuit of the control unit are arranged outside of the casing of the optical system unit and are connected to the optical system unit through a light guide member that guides the secondary light from casing of the optical system unit to the photodetector, and
• a connection portion that is placed between the light guide member and the optical system unit and that connects the light guide member and the optical system unit, the connection portion being configured to allow adjusting a position of an incident side end part of the light guide member relative to the flow cell.