A keyless engine controlling unit has a set switch for setting an engine in a running state, a selected state detecting mechanism for detecting the position of a select lever of an automatic transmission, and an engine drive controlling mechanism for bypassing a contact point of an ignition switch. During engine operation, the selected state detecting mechanism detects that the select lever is in park, the set switch is set, and the contact point of the ignition switch is bypassed. Thus, the engine is maintained in the running state even if the key is extracted from the ignition switch.