PURPOSE: To enable the condition of a car to be checked during washing the car in a car washing apparatus provided in a gasoline station by arranging an engine analyzer in a vehicle stopping position during washing the car.

CONSTITUTION: Car stoppers 5, 5' are provided on the ground through which rotary brushes 2 of a portal car washing apparatus 1 pass, and a detecting portion 6 of an engine analyzer is provided near the stoppers. This portion 6 is constituted from a planer body having a built-in coil for detecting electromagnetic wave produced by ignition plugs. Thus, when an engine section of a car being washed is stopped to be located right above the detector 6, ignition signals of engine plugs are detected during washing the car by the detector 6 and sent to the input of a calculating circuit to judge the condition of the engine and indicate the result on a judge indicator 7a, a dispersion indicator 7e, a mean rotational frequency indicator 7b and max. and min. rotational frequency indicator 7c, 7d. Thus, the condition of the engine can be checked while the car is washed.